I'm speaking in generalities. There are theistic evolutionists who are not actively trying to troll the Web and recruit Bible believers away from their faith. Also, there are yet a few professing atheists who really don't care what the rest of us believe, and want to go on about their business.
A foundation for the religion of atheism is evolution, which gives many professing atheists a "scientific" explanation for the origin and development of life. Naturally, atheists attack Christians because it's their nature to do so (John 8:44, Luke 6:22, 2 Timothy 3:12). But they hate creationists even more, because creation wrecks their evolutionary foundation. When it comes to biblical ("young Earth") creation, they ride in at full gallop with guns blazing, because evolution requires time — a lot of it — and biblical creation science shows not only the flaws in evolution, but gives evidence for a recent creation.
However, professing atheists are willing to sit down and play a few hands of poker with compromisers on creation. OECs ("old Earth creationists") are tolerated because they accept atheistic interpretations of scientific evidence. More than that, they are very fond of theistic evolutionists because not only do TEs reject the plain teachings of the Bible regarding creation, many join with atheists in riding for the evolution brand. In general, TEs and OECs reject the Bible's account of the global Flood.
To say that God used evolution is downright silly, old son. Evolution is a wasteful and cruel. It violates Scripture, the nature of God, and good science. God completed creation in six days (Exodus 20:11) and said it was very good (Gen. 1:31). Adam was complete right away (Mark 10:6). No long ages, bloody struggle, survival of the fittest, dead ends, or any of that. Also, if death and suffering were a part of the way God did creation, it's mighty strange that the Bible refers to death as an enemy (1 Cor. 15:26), not one of God's creative tools. At the final consummation, there will be no more death (Rev. 21:4). No, you can't say that God used evolution and be consistent with the Bible.
Both atheists and TEs will use appeals to authority or to popularity in an effort to bushwhack biblical creationists, saying things like, "The Pope and the Roman Catholic Church accept theistic evolution", or, "Biologos believes it". What are they expecting? That we'd say, "Oh, well if they believe it, I'd better change my views." Not hardly! That doesn't make evolution right. Also, some of us don't cotton to throwing in with false doctrines just because someone else is doing it (1 Tim. 6:3-4).
No wonder the whole passel of sidewinders share a table — they all reject the authority of Scripture, and the compromisers (sometimes called "reasonable" or "honest" Christians by tinhorn atheopaths) are well down the road toward atheism. And yet, the professing Christians in that gang often claim to believe the Bible. Do they? Let's have us a look-see at what effect theistic evolutionists are having.
Many TEs work with atheists to ridicule biblical creationists because evolution is more important that what Scripture teaches about how Christians are supposed to treat each other; mockery and abuse are not in the canon. When evidence for a young Earth is presented, or when evidence refuting evolution is given, they circle the wagons and open fire on those of us who actually believe the Bible. (Looks like Paul was talking about something else when he said that we are supposed to be destroying arguments and strongholds against the Word of God, 2 Cor. 10:4-5 ESV.) Today's culture has many pagan elements, and Christians need to start with creation in our evangelism efforts. F'rinstance, when Paul argued with the Greeks in Acts 17:22-33, he began with creation because the Greeks were evolutionist pagans, not monotheists.
For that matter, I've been attacked by theistic evolutionists who were so vituperative, I thought they were atheists! Same bad reasoning, condescending attitude, equivocating science with evolution, giving science philosophies (which change and disagree with each other), the magisterial position elevated above Scripture, and so on. No wonder I thought the professing Christians were atheists. (Actually, some of them are atheists; I've caught them lying and pretending to be Christians, such as this one.) Interesting how they claim to love science, but refuse to consider how the biblical creation model makes more sense than evolution.
Theistic evolution is a denial of God's Word, and therefore a false teaching. Certain TEs are enabling atheists in their rebellion against God by affirming the atheistic belief in evolution. What is worse is, again, how they will join forces against biblical creationists in strong mockery and ridicule, including defamation — they encourage hate (Rom. 16:17-18, John 13:35). They are false teachers (Eph. 5:11, Matt. 7:15-20). Would Jesus approve of such actions and attitudes?
Some TEs spend a great deal of time and energy in this ridicule. Calvin Smith of Creation Ministries International (a former atheist) was the latest target of mocker Tyler Francke. In addition to Francke's characteristic condescension and complete lack of respect for people, he resorted to using screenshots of e-mail correspondence. These hate mails against Calvin Smith were initiated by angry apostate "Haywire the Stalker" (Ashley Haworth-Roberts, and you can see some screenshots of my evisceration of his "logic" here, click each image to enlarge). Both Francke and AH-R crave attention, and I'm not happy about giving it to them, but it's necessary so you can see some of how depraved both camps can be.
Instead of joining atheists in ridicule and defamation of Christians who believe that the Bible means what it says, we are supposed to be proclaiming the gospel and destroying unbelievers' strongholds — not building up their foundations and enabling them in their suppression of the truth. Try to find what these professing Christians that adore evolution have to say about grace, sanctification, propitiation, redemption, the gospel message itself (especially salvation and justification by faith through grace), love for brethren, and the authority of Scripture. See if they glorify God, and show good knowledge of Scripture. I reckon it's safe to say that those who strengthen unbelievers in their rebellion will have to answer to God as to why they attacked Christians and helped unbelievers cling to their fundamentally flawed worldviews. Also, note the tone of the comments from anti-creationists (most of whom are atheists).
An added note: OECs and TEs send a mixed message. Many claim to believe the Bible, but then insist on interpreting the first eleven chapters of Genesis according to naturalistic views, presuming to tell God what he said and meant. That's called eisegesis, which is the only way to get mega-years and evolution out of the Bible, it has to be put in first. It's difficult to witness with a Bible that they say can't be trusted at the beginning (2 Timothy 3:16-17, Prov. 30:5-6).
I believe that many theistic evolutionists are not Christians, but are instead deists who have twisted God's Word to suit their own fancies. This is idolatry, and they need to repent. Some may need to repent for salvation, and some for their abuse of Christians and their support of unbelievers.
ADDENDUM: A companion piece of sorts is "Making God More Attractive Through Evolution".