A third-party vote is a vote for Trump.
Im gonna put a theory out that I havent seen here yet, a lot of people voted for Trump because they got dunked on by leftist Twitter, told they were racist/fascist/whatever for having an opinion like "communism is bad", and now comes a guy who wont back down and who legit makes them cry liberal tears. Ever been pissed off at someone with no recourse? Of course they want that kind of satisfaction.
Because if that is true, you're re-writing the rules of your "personal voter math" to fit your narrative, and if it isn't true, your "personal voter math" === your opinion, which isn't really useful.