Well you're free to think whatever you want about BLM, but some sort of protest or statement was happening all over the world both in on- and offline communities, so you're not really singling out Reddit here, this is just an instance of a general trend.

Plus, my statement was about "heated political arguments", not a one-time statement from moderators which remains, to my understanding, rather rare. One thread about BLM doesn't deter me from visiting these subreddits.