What they fail to recognize is that I have taken all of those 101 courses. Just because I pass a course doesn't mean that I agree with all the conclusions drawn by them.
I remember when I took a biology course on human evolution and the professor started the course explaining that they knew some people might be uncomfortable believing that humans evolved from apes. She said that she didn't expect you to believe it, but she expected you to be able to explain the scientific position on it.
You have posts here where you're not just disbelieving some thing, but you're exemplifying that you are not able to explain, and do not understand, the scientific position on it. And that's fine, and you're right that people shouldn't assume that you haven't studied it at all.
What rubs people the wrong way, is the sense of arrogance that comes off from a person who proclaims knowledge on a subject while displaying a lack of understanding of the subject.
If someone said they knew your religion was wrong because of the story of Jesus parting the Red Sea, wouldn't you be a little peeved?
We're not here to convert you. Or to be against you (apart from positions in a debate). We're here to discuss.
The way you approach the discussion is what determines how you'll receive from it. Ask, don't tell. Question, don't answer. Be open, not closed. That's the way to a fruitfull discussion.