I just don't understand why open source software can continue with the assumption that every single contributor is honest. Imagine if this philosophy was applied to, say, cryptography or network security. What would be the state of encryption algorithms and key exchange protocols and so on, if their developers had a meltdown at the mere suggestion of there existing a liar?
Since the Linux kernel is installed on many millions of computers, it is obviously pretty important that it doesn't have bugs in it. Certainly not malicious bugs. And if all it takes is a couple grad students and an assistant prof to get them in...well, that reflects very poorly on the state of kernel maintenance, to me. Which seems far more important and deserving of attention, than endlessly arraigning three clueless guys at some university.
I'm not in a position to be more specific about what should be fixed. But, what would your answer be to your query? Apparently, do nothing, and assume that everyone in the world is honest, while writing self-indulgent "public letters" about it? How is that going to help when the CCP tries to insert surveillance into the kernel? Or when Russian hackers try to get exploits and ransomware in there?