If 2016 taught me anything it’s to not trust polls. Doesn’t matter how hard ahead Kamala is polling until your ballot is actually cast.
It also doesn’t help that you have the “Lemmy.ml” crowd calling you a fascist if you vote for Kamala, because in their twisted world having trump win is better eomehow
To your second point, it’s because most of them hate the US and/or capitalism, and want to see it implode.
That would be terrible for worldwide peace and stability. US has too much power and influence for an implosion to not cause worldwide chaos. Trump would mean US siding with other dictatorships, like Russia, China, Iran. Russia would likely succeed in Eastern Europe. Taiwan would likely be occupied by China. NATO vs an alliance made of US, Russia and China would be very uncomfortable.