It's a mix of a few things, the most important and easily missed nowadays is this particular thing happened when the extreme left was in near total control of the culture war. Some people didn't push back out of fear they'd be doxxed, their employers contacted, and lose their job (fear of being called racist or pro-slavery). Others thought it was so small it didn't matter. Others did it to just shut up the people piling on. Most normal people at this point hadn't even heard of the culture war, so trying to explain anything made you sound like a crazy conspiracy theorist, so still others just didn't want the hit to their reputation.