@Maudia Who knows? Maybe it'll get more apparent once you get out of your twenties.
If an INFJ is fighting for something, this is because they believe in the idea itself, not because of some selfish reason.
I can understand why it's so rare, though. The idea of someone fighting only for what they believe in and not switching around viewpoints to suit their own goals is pretty jarring. Almost creepy even.
If this is your actual personality type, I am more than a bit scared of you.