It could easily cause some painful embarrassment, but hopefully that would pass with time.
Maybe embarrassment similar to that faced by researchers who's results suggested FTL communication, but it turned out to be a bad fiber-optic cable. I didn't follow up but I assume that team is doing OK.
Sometimes the courage of your convictions means trusting the process to get it right when you're sure you're wrong.
https://www.newscientist.com/article/dn21656-leaders-of-cont...
I think you mean "cojones" (which btw is a very rude word in Spanish). A kahuna is a kind of Hawai'ian shaman.
Bollocks, like many slang words, have multiple meanings in different contexts. It can be used as you stated as well, but "What you said is bollocks" and "You have bollocks for saying it" are very different statements.
Why? Why should posting a stab at a complicated problem should be considered career-killing?
There are people who point at others' failures to bolster their own image by comparison. And there are people with fragile egos who are eager to see others in a negative way.
It shouldn't be that way, but it sometimes is, so I wouldn't say the career risk is zero. But I'm still glad he's doing it regardless of the outcome.
https://en.wikinews.org/wiki/Researcher_claims_solution_to_P...
https://arxiv.org/find/all/1/all:+AND+Vinay+Deolalikar/0/1/0...
He is still publishing papers. Seems to be doing fine.
If I were a betting man that's actually where I'd put my money because the paper passes by bogometer test (but I am nowhere near qualified to assess whether it's actually correct).
He is a tenured professor in Germany, there is very little that could end his career (essentially refusing to honour his teaching obligations or being convicted of a felony). At worst, this will be immensely embarrassing, but you can't kick professors out just because they make a fool of themselves.