That's not shroedinger, that's just logic. Hard concept for some people on here, it seems. For how well you understand right wing politics and tactics, it's suprising you believe that the "left" wing would be much different.
Let's say I need 51% of people to vote for me. I can get 41% with all the standard talking points of making things slightly less shitty. 10% I could get by shouting about the genocide in Gaza, but then I'd LOSE some from the 41%, because "I'm too extreme". In this scenario, the leftists are responsible, AND not significant enough to pander to.
When a nazi sees a conservative and a democrat on the ballot, do you think he doesn't vote, because the conservative didn't call for the gassing of Jews?