It's at least in part Russian propaganda. They don't want people to vote for Trump, they do want democratic voters to not vote at all, which will help Trump get elected.
Look at the people pushing the 'genocide Joe' thing. Invariably they're anti-NATO and make excuses for Iran, Syria and Russia. Not that they're doing it deliberately, but plenty seem to have bought the propaganda and are acting like useful idiots by spreading it.
You're may be right. I assume most of them are 'useful idiots'.
They realised western media were often biased, so they switched to 'critical' media, spent more and more time in internet bubbles, and ended up uncritically parroting Russian, Chinese or Iranian propaganda instead.
Same thing happened after 9/11 and Iraq. A lot of people were angry about how biased CNN was, so they switched to channels like Russia Today because it was critical of the US and did genuinely have a lot of good journalism. Of course, that doesn't mean Russia Today isn't propaganda. A lot of these people are forever lost, I don't think you can deprogram them.
Also if people use a lot of slogans like "cultural marxism", "Fuck Brandon" or "genocide Joe", without being able to articulate a nuanced position, it's likely they've succumb to newspeak. Newspeak uses an impoverished and simplified vocabulary, to prevent people from critical thinking.