Tell them they have to vote for Jill stein because it's her turn.
And then really put your foot down and demand why that isn't a viable reason anymore.
My other favorite is when they say if you aren't voting for Biden you're voting for Trump.
Tell them you also aren't voting for Trump, which means you are voting for Biden (unless that thing they just said was horseshit) so effectively you're voting twice without breaking any rules, and ask them why they're only exercising half of their right to vote compared to you.
That last one doesn't land on libs because in their mindset Republicans winning is like the default. It's like the natural flow of how America works, but Democrats are like the counter balance to assert liberty or freedom or whatever. So they believe any neutrality is inherent support for Republicans.
West Wing brain is far worse. Its default assumption is that the president is a democrat because people feel better that way, but at least one chamber must be republican to protect their lanyard-in-chief from facing any expectations other than bipartisanship.
She ain't gonna win anyway, and it's not like Dems are gonna go antivax and pro-Russia to court the Green voters who are antivax or pro-Russia. I think practically voting for her is sending the Dems the message to just go left, which is better than voting for Dems and giving them the message that leftists will keep supporting them even when they enthusiastically support genocide. However, you'd achieve the same thing by voting PSL and PSL doesn't have antivax brain worms.