It's not bizarre at all. The math community has unfortunately been down this road many times before. When an 80-year-old announces a 7 page proof of a famous problem, the smart money is on the proof being wrong. As the comments elsewhere on this story indicate, this heuristic turned out to be correct. The only new twist is that we have two 80-year-olds this time, not one.

To be clear, I don't like this state of affairs. As suggested above, the best course of action seems to be to ignore the posting.