The answer is simple: "evolution" is bad science, "evolutionism" is a false counterreligion, and "theistic evolution" is syncretism.
Certain kinds of microevolution have been directly observed. But this is not incompatible with young earth creationism, and microevolution doesn't entail other kinds of evolution.
Macroevolution and cosmic evolution have never been directly observed. What we have is unclear, ambiguous data that could go either way. The only reason why so many people believe in evolution is because they are spiritually blind. They assume up front that young earth creationism is absurd (or at least wrong, not to be taken seriously), so they go with the only other option that they've ever been taught (or, the option that they judge to be more "likely" or "probable", the only option which they take to be worthy of belief).
There's no point trying to reconcile evolution with Christianity, unless you want to be a heretic and believe in absurdities. Evolution and Christianity are irreconcilable. The God of Christianity is simply not the same person as the "God" posited by theistic evolution, and Christians are definitely not free to reject the fall of man (a doctrine which entails that the world was not always imperfect).