Are we both reading the same GP comment? It reads as "If he took this stuff seriously, he wouldn't have waited 12 years since SHA-1 was broken to even start considering any changes.".
1. Saw a known issue that cryptographers and security people were warning him about.
2. Alternatives existed that didn't have that issue. People were pushing on it.
3. Ignored all that to tell them it wasn't a problem, the issue could never have real-world consequences, and he wasn't interested in fixes.
In practice, that means he didn't take it seriously. He also made sure it wouldn't get fixed by letting people know he wasn't making a change to it. One more example in a long line of them where Linus doesn't give a shit about security enough to apply known, good practices.
Given this context, of course nobody wrote patches: they would have obviously been rejected and been a total waste of time. Until now, when we actually have to deal with it.
This is all aside from your argument being fundamentally weak, however ("you can't criticize anything unless i say so and contributed by meeting this arbitrary standards. i mean, didn't do anything either, i just get to make up the rules you abide by!!")