It's not ridiculous because they can be destroyed eventually, its ridiculous because it has no basis in fact. There is no evidence, nor theoretical position that supports the claim that UVA or UVB plus touching with hands will cause any noticeable degradation of a ballot. This was nothing but a spell cast. People will be inclined to believe, without evidence, anything that they fear might be true.

If they have insufficient knowledge on a topic, that is the most likely scenario; i.e. someone will choose to believe something if you give them a reason to fear it might be true.

Of course it takes 15 seconds of experimentation to show how its not true, but that's work. Work is hard. Belief based on lies that cause fear is easy.