As for keying: I don't really condone it, but if you're close enough to me that I can't get in without my car door touching yours, I'm not going to become a contortionist and/or crush my own fingers to keep it from touching yours. If it scratches, don't park so fucking close next time.
And yeah, it could have been someone else's fault, but park elsewhere if you see that issue arise. I am not going to feel bad for trying to get into my own car when my door isn't even leaving my own space.