I don't think you'll find many people that would ever personally be pissed at a player for not being talented. At least nothing beyond getting caught up in the moment at games yelling out "you suck, [insert name]", "damn it, [insert name]", etc. That just happens. I won't say that hearing that doesn't affect players. But, I would think most players are too focused on getting their jobs done on the field to let that bother them too much. That kind of behavior has been around forever and always will be. If you are physically talented enough to receive a free education to play a sport, I'd say you can deal with the occasional boo bird from the stands.
I also think its fair game to be pissed/critical if said untalented player was the best option we have to put on the field (thanks, crooms!). But, that should be directed to coaching staffs versus players that bust their asses off on and off the field. Fervid criticism of coaching staff performance is well merited when the head coach is or is being made a millionaire.
All that being said, kicking ZS while he's down is a low blow and generally ****** thing to do. I agree - lay off the guy.