Sure, but it happens all the time with "professional" science too. This guy did nothing that isn't seen every day in the literature.

The reason these people didn't check the claims is because they have an extremely strong culture of never checking any claims. If they did they might discover the claims were false, and then they might feel obliged to attack a colleague who realistically will be protected by their institution, and who might be a peer reviewer or even colleague in future. So, ignorance is bliss.