Ronaldinho did it every game, no matter the score.
That was part of his game.
Neymar does it to taunt the opposition.
As the saying goes, Kicking a man when he's down.
The Costa Rica game is the perfect example. Massively up against it. Gave it their all for 90minutes, conceding near the end, then having somebody flicking it over their heads to add insult to injury.
Neymar is an exceptional player, I've not said he isn't, but what he does, when he does it is unnecessary.
Sure, if after 20mins, 2-0 down he wants to beat a man with a rainbow flick, then do it, but does he? No... Wonder why