You have no right to rage and intentionally do bad in your role if a teammate bans your pick if...
You have absolutely no right and do intentionally bad in your role (example: playing a bad champion for that role -soraka jungle, vi support, etc..) if your pick gets banned by a teammate if one of the following occurred:
-
You didn't make your team aware of who you were going to play. Ex: pick them, tell them 'don't ban _____', or even just plain saying, "I'm playing ___".
-
You got autofilled and decided to go with the champion you were going to play anyway even though you got a role that doesn't fit it.
-
Had a fight with a teammate in pre-game chat and decided to go someone that completely ruins everyone's game experience just because you're mad at them.
I'd like to highlight #1, as it is the least obvious to some people who rage over their teammate banning their pick.