Yes, airlines literally have failed to keep customers comfortable, that's the entire point. Zero people are comfortable on that flight, and everyone knows that when someone reclines back into them it becomes even less comfortable. You aren't making your experience better, you're making someone else's worse. The airline failed by making seats uncomfortable, and you're making a bad situation worse for the person behind you.

Just because you can do things does not mean that you aren't an asshole for doing those things. You're allowed to block aisles in a grocery store, to go slower than the speed limit, to buy the last two packages of cookies when you know the person next to you also wants one, you're allowed to do lot's of things in life. It doesn't mean you're not an asshole for doing it. (In fact the entitled attitude you have without a care for anyone else kinda really drives home that you are)

If no one is behind you then recline away.