Riot is the sole actor to blame for the mess Boards became.

Riot chose to not listen. Riot refused to be held accountable when the players almost universally cried out on Boards/Reddit. Riot pretended that the universal outcry was brigading, not the fact they fucked up. Riot abandoned their official platform because they couldn't be bothered to put up the effort. Riot made the conscious decisions leading up to the community naturally being more toxic.

When you don't take the time to sift through all the flak to pick out and handle constructive feedback, you show that you want an echo chamber where nobody disagrees. This was seen several times since the original move to boards. Riot also demonstrated poor management of the mess, trying to sweep it under the rug like none of it ever happened. They kept trying to ignore the massive pile of filth they allowed to accumulate in the corner of the room while it kept taking up more and more space.

All in all, the community's response to Riot's negligence was natural. For Riot to pin everything on the community is a show of entitlement and ignorance. This isn't to say there weren't bad actors before. Just that Riot created the situation where fewer people were willing to be reasonable because Riot itself was unreasonable in the first place. There will almost always be community members unwilling to be reasonable. So it is inherently on Riot to remain reasonable despite said unwilling community members as a show of faith that those bad actors were not representing the entire community.

I'm disappointed Riot chose to close boards not just because it's actively shutting down a community I was a part of (despite several issues); but because it sets a precedent where "official" contact with the devs of any game company should be centralized in something like Reddit or Twitter. However, that's a discussion best left for another thread on another platform.

I hope Riot eventually turns their game around. Not simply League, which has definitely been deconstructed since the Juggernaut Patch in late Season 5. Rather, their game in PR and working with the community despite the bad actors. If Riot shows that it's unwilling to ignore the bad actors to respond to the good ones, then the good ones are less likely to remain reasonable when Riot finally does get to them, if at all.