The backlash came to a head due to a combination of a few things.
- Lightfall release was a mess, and not well-received. Primarily walling off lore in the paid-for seasonal content did NOT go over well at all.
- Consistent server problems (much worse since Lightfall dropped)
- Cheating in PvP (which there has been a decent crackdown by Bungie recently)
- The announcement of Marathon (where all their primary PvP devs went)
- The video by streamer Aztecross on monetization creep in the game, and subsequent responses by other streamers.
- Silence from Bungie, or updates such as this one that don't really adequately address the message players are trying to send.