The main outrage in the Neymar transfer was about him stabbing us in the back and leaving like an idiot, tossing in the trash all the 4 years he spent with us. Most Barca fans don't care about keeping a player who doesn't want to stay. I remember Barca fans wanting Neymar out after he betrayed the club.
If Neymar said publicly he wants out, he'd have been sold. Simple as that. With or without the buyout. But he was a chicken shit and was too scared to face the backlash from fans by being open about his intent to become a PSG player this summer. Coutinho made it clear that he wants to move by handling a transfer request, was pretty honest and straightforward with Liverpool. Neymar never did that until he signed with PSG. So there's no comparison between the two.