Just because most games do it doesn't make it right.
They allowed sales of the game in countries where you could not make a PSN account for one, only to bait and switch those users long after the grace period for refunds had expired on Steam.
Also, there was no need for a PSN account for Steam users. They cite things as "making the game safer for everyone", which doesn't make sense considering how often SONY has leaked user data.
The fact they the game is so beloved by a community that is also large and organized is probably what led to such a massive backlash in such a short amount of time.