Yes I know, your least-favorite idea goes here. But seriously, someone must have come up with the concept before. Like a bad get-rich-quick scheme could fall into this category, where joining the scheme makes people lose money and become more desperate, so they become more likely to do desperate things like invest more in the scheme. But it can apply to a number of other bad ideas.
Perhaps the closest term is “cognitive dissonance.” I don’t think current usage best fits your description, although the original event that inspired the term certainly does.
https://www.simplypsychology.org/cognitive-dissonance.html