It's mostly done to trigger conservatives.
No Mutants Allowed
Morgan_
People are still talking about Bioshock Infinite?
mustadiokeepsdying
No, both are just examples i came across randomly.
Atomic Postman
It's not about being cool my dude.
mustadiokeepsdying
What is it about?
Morgan_
Being gay obviously 
Atomic Postman
Supporting pride in a way that costs nothing and is just kinda fun
"mustadiokeepsdying says X Pride"
See? Even I can do it!