If you looked at one election cycle in isolation this argument makes sense but when you view it in the context of several elections it has a fundamental flaw. Yes, Trump is an existential threat to this planet but so are the Democrats who have demonstrated that they prefer someone like Trump in the White House to someone like Bernie Sanders and will move heaven and earth to make sure he doesn’t become the nominee.

If (as is likely) the competition is between Biden and Trump it will not be a democratic election, it will be a setup and you’re asking voters to make an effort in what can be justifiably seen as a pointless exercise. Biden isn’t even capable of running a presidential campaign (he even forgets the name of his old commander in chief).

Truth is the President is chosen by the 1% and the only choice the people have is between a horrendous president and and an awful one. If you want people to get out and vote you need to give them some hope first - otherwise its cruel.