Whee! Ok, here we go.
First, let me apologize for the "bible thumping" types you seem to have run across. I'll mention this attitude later.
Secondly, if you believe that what a person is saying has no validity, then how are they imposing anything upon you? No one has a gun to your head, right?
Christian beliefs - I'll get back to that in a moment.
Evolution is a theory. It's not a law. You said in an earlier post that it exhibits the scientific method, but there are a number of respected folks in the scientific community who'd disagree with you, without needing to propose an alternate answer such as creation. BTW, I strongly disagree with your statement that science and religion is like oil and water. Why should they be? There is, after all, only one explanation of how we got here. Both science and religion can, and should, be on the side of truth and fact.
Yes, evolutionary theory should be taught, as a theory. And creation should be taught, as what a group of people believe. And when the kid asks the teacher about the beginning of life, the answer should be "I don't know." Just as there are mindless fanatics on the creation side of the issue, there are mindless fanatics on the evolution side who couldn't tell you why they believe it or address the issues any better.
Now then. Christian faith. You say you would call yourself "somewhat of a Christian". Based on what? The (almost exclusive) record we have of Christ's life is in the Bible. That Bible, and Christ's own words, repeatedly make the point that you're on one side or the other, and that fence-sitters are nauseating. You have either accepted His gift to you or you've not. Note that I'm not telling you what to believe - I'm telling you what the Bible says. Whether or not you accept that authority is up to you.
Today's "Christian" culture is, well, phony. Going to Christian church makes you a Christian like going to a garage makes you a car. Are there Christians there? Maybe. Are there people who call themselves such, but aren't? Pretty likely. Is it the duty of any man to get up in your face and scream that you're going to hell? Very, very unlikely. I say that because, y'know, God can use ANYthing! But that doesn't make it right. We're supposed to be loving! WWJD, and all. But, would you let someone you loved walk alone and unarmed into a dark alley where you know there's muggers? You would, at bare minimum, want to warn them, and you'd probably plead with them not to go, especially when one street down there's a nice, well lit and safe path. THIS is the kind of concern that should be shown when a Christian shares their faith, not "You stupid (bleep), don't go in there!"
You mentioned corruption in the church. You specified Catholic, but can apply anywhere. In short, men and their institutions are corruptible. That's why we need God, after all. When the layman can't or won't read the scriptures he's supposed to obey, that's a wonderful opportunity for the crook, isn't it? That's one reason Paul said we should follow no man but Christ alone.
We are supposed to give of ourselves and goods to the church, and the church is supposed to help those in need. The early Christians were almost communal!
Nature: Again, many places in the Bible, we are told to be good stewards of what we're given. That means responsible use of resources like trees, water, animals, and energy, among other things. Greed is also obviously to be avoided. (There's more verses about dealing with money than hell.) God would therefore seem, at least in this respect, to approve more of the naturalist than a money-grubbing corporate pirate, neh? But not if he's killing people who are chopping down trees.
Biblical references can be easily provided upon request.
