The only reason not to do so is the vanishingly rare chance that democrats turn a red state, which is basically the exact same argument they use to tell people to vote blue no matter who, but more compelling because it’s not typical genocidal am*rican politicians they’re voting for.
What are they going to do? Tell you they want to vote for a war criminal on principle? The positive political pressure of having a somewhat popular socialist party far outweighs the small chance democrats could have won (and this is even from their perspective, that the democrats winning would fix everything somehow)
According to this access chart, they have write-in access in Pennsylvania as it is one of a few automatic write-in states as per the EAC, meaning they don’t need to register as an official write-in candidate to be written in like they would have had to in Georgia to receive write-in votes after they were fought off the ballot there as well by the (anti-)Democratic party capitalist superPAC lawyers. As far as I know write-ins still work in automatic write-in states as it is unnecessary to register for an “official write-in status” because it’s automatic. I could be wrong if someone has better information but it’s what I am seeing.
They have automatic write-in access in Alabama, New Hampshire, Oregon, Pennsylvania, and Wyoming. Registering is specifically for ballot access in states with automatic write-in access. So my assumption with them being removed from ballot access proper by the (anti-)Democratic bourgeois party’s superPAC lawyers, is that they now can only be written in and can’t be chosen directly on the ballot. Assuming the ballots aren’t reprinted because it’s so close to the election, you would presumably void your vote by choosing them on the proper upper ballot (which they’ve been “removed” from) vs writing them as a write-in where candidates have automatic access. This is my assumption. Certainly, granted, it would be totally asinine for them to have it pan out this way — but also US bourgeois democracy is totally asinine, and that’s the info I have.