It doesn't have anything to do with the players, it isn't about sparing their feeings, it's about sparing MY feelings. I'm sure they're well aware how toxic fans can be, and completely steer clear of this sort of social media unless they like being all depressed after listening to a bunch of cranks and teenyboppers rip their performance to shreds every week.
However there are a large number of fans who are stoked about the team and don't appreciate their forum being monopolized by this kind of 'fair game' criticism, no matter how demonstrably contrary the reality may be. Hell look at the way you talk, that's what being a fan is to you, watching the game and then hitting the internet and venting your spleen. There are tons of fans - a silent majority let's say - who don't feel any compulsion to be loud armchair critics feasting on all the various shortcomings of their players on their own roster that they at least nominally support, but apparently they have no choice in the matter. Because being a fan IS being a 'hater' according to you.
So if you're dead set on cashing in on your birthright as a fan to bag on your own favorite team even after a particularly impressive and important win, at least make sure when you get your licks in that they're halfway cogent and reasonable and not wild and irrational and boring as they so often are.
One last thing, when you can't understand why someone is starting 'cause they seem like they suck so bad? It's probably because you're wrong and the coaches are right. As in they don't play shittier players for no reason, or any reason at all really. And the main reason is usually going to be however much the player you think sucks so bad, he's probably better than the alternative, and that's why he's playing.