“Just vote straight party. Obviously the people who did these quickie ballots weren’t very smart. They were told to vote for Biden, not the Democrat slate.”
Maybe voting for the down tickets would open them up to state and local scrutiny. (Just a speculation)
I have been thinking about why the fraudsters did not go down ballot with the cheating.
One reason might be that many local races are non-partisan (like city council, judges etc.). In addition, many states have ballot questions/referendums.
So, faking a down ballot is rather complicated—not worth the effort.