Accompanying the sloths, of course, you had a pair of pythons, a pair of capybaras, an assortment of tree frogs... and this was also around the same time that the kangaroos, wombats, thylacines, and koalas all said "Hey, we marsupials have to stick together, let's all swim along the Polynesian islands together until we find some place to set up shop." ... You really don't need paleontologists and geologists and geneticists to build a case and present scientific evidence against Creationism - you just need to step back and allow it to collapse on its own.

Creationism hurts Christianity.

Of course, the number one reason that young adults leave the church is unloving behaviour from its members, but I'd say the #2 reason is the refusal of religious leaders to sync up their dogma with reality. Creationism is the most blatant example of that, but you can also see it whenever someone with authority but no secular education or experience gets behind a pulpit and begins to lecture their congregation on sexuality or economics or obstetrics or world history or other religions - particularly when they present this lecture as incorporated with and inherent to Christianity itself.

If you force people to choose between their faith and reality, you're going to wind up with either a bunch of jaded nonbelievers or a bunch of wide-eyed zealots who can no longer meaningfully engage the world outside their religious subculture. Both are undesirable outcomes.