This argument starts with the assumption that Biden is bad but Trump is worse. The goal is to minimize Trump’s relative score compared to Biden.

So there are 3 options:

• vote for Trump, +1 to Trump’s relative score
• vote for Biden, -1 to Trump’s relative score
• vote for neither or don’t vote at all, +0 to Trump’s relative score

Voting for neither or not voting is 1 point worse than voting for Biden.