how do I deal with overly agressive christian friends?

maybe try telling them to respect your opinions a bit more if you say no, you mean no they cant ask for respect unless they show other people respect

Do you mean they preach to you about right and wrong etc? It sounds like they have strong opinions on certain things and nag you about things you do that aren’t considered right in their minds. It’s a matter of opinion, morals, and beliefs though. I personally am into God I believe in all that, but I am not going to sit here and say I’m going to go to hell for masterbating, or having sex before marriage, drinking…none of the above. Others may believe just the opposite, it’s a difference in upbringing. Just tell them to respect your opinions and you will respect theirs, end of story. If they keep pushing, get new friends because they sound a little judgemental.

You dont have to be aggressive. Just assertive. Listen, just because someone has helped you out and you feel like you owe them, does not give them permission to disrespect you. Which is exactly what they are doing. You cannot tolerate stuff out of a sense of guilt. They were being friends when they did that stuff. No expectation in return. Be upfront with them. You understand that they mean well, but those are not your beliefs and they need to respect that.