It's one thing to say that mail in voting could potentially have security issues. It's another to say that Democrats plan to light ballots on fire. In order to legitimately claim that with any certainty they would need actual proof of someone developing a plan or expressing an interest in doing so. They clearly don't have that. Maybe "false" or "misinformation" are not accurate enough terms but I think "unsubstantiated fear-mongering" is fair and would have the same effect.