The US constitution is an arcane and undemocratic piece of crap, and it does not afford us the luxury of abstaining from a federal election.
As much as I wish I could avoid voting for a flawed person, we legally do not have that option.
The unspoken, background racism of the US is deadly enough. Any of Biden's detractors should know that. But Trump compounds the problem by actively, specifically, acting against entire groups of people, and it should be obvious how much more dangerous that is.