I don't condone insulting people, but I can understand we as a community's frustration with people like that.
For one, people who make post about quitting Destiny rarely actually give feedback, just reminds us of how the game sucks. Negativity is something that we need no more of in this forum. These "I quit" threads are generally filled with insults to the game rather than actual feedback.
Actual feedback doesn't announce they're quitting. There's no reason to say such, if you have feedback, give it. There's no need to say "I'm quitting" like you were a crucial focal point in the Destiny community.
As a person who really likes the game, I don't mind feedback, hell I welcome it. It's what's shaping the game today and why most of our complaints are being dealt with. But, keeping in mind that I like the game, it irks me when people basically bash the game. How would you feel if a group of people or person kept saying something you liked sucked? Your car? House? Favorite sports team? Your mate? You'd likely get agitated after a while.
That's why I really have no sympathy for those people who make "I quit" post that don't give real feedback, just looking for attention and an opportunity to say Destiny sucks.