I think 4chan is a shit hole and do not in any way approve of them mocking BLM or the movement.
The reason I share this however is to point out the generally harmful group think of people being activists right now, to the extent it is hurting the movement.
4chan consistently has success in these matters. Right now its Bald for BLM which seems to be catching on, and not that long ago they managed to trick everyone into thinking the OK hand gesture was a white supremacist hand gesture and even managed to get it on a list of hate speech.
When 4chan is this successful at manipulating people simply by making something look popular, when that is the only criteria for success, its time to reevaluate the underlying mentality driving our activism.