AFAIK there isn't really any evidence that anyone at UMN was actually trying to get a know-bad patch into the kernel. The only patches that we know had deliberate vulnerabilities were the ones discussed in the published paper (K. Lu, Q. Wu), where they took steps to ensure the changes would never actually be merged (and submitted corrected versions of the patches after the initial 'malicious' patches had been reviewed). The later patches submitted by A. Pakki (which were the subject of the email thread where Greg KH ultimately banned UMN), don't seem to be deliberately malicious. More like he tried to write an analysis tool and either did a half-assed job testing/validating it or was trying to get the kernel maintainers/community to do the job of testing it for him. The methods of the former were questionable and the behavior of the latter was unprofessional (to say the least), and I can see why it pissed off the maintainers. But I don't see either as trying to get known-bad code into the kernel. For example, I don't think pull requests for any of these patches were ever created (which is done to start the process of getting the patches integrated in the kernel). It seems the patches were just submitted for review via email and never went further than that.
Talk by Greg KH of ripping contributions out of the kernel were referring to all patches submitted by people with umn.edu email address ever, not just the "hypocrite commit" patches, and not just the 3 people mentioned in this article.
Though I cannot say you are wrong with the assumption you made, but being part of the academic circle my self, i think it unlikely. Greg made it manifest that he saw the code that he banned them for was deliberate and malicious. If you have a look at the justification they made to Greg, and the Lies they then published, Greg said that they were trying to say that they deliberately put the code in to test Greg and his team. This is not only unethical, but also unlikely. You do not put code of this nature in a Kernel, that is not a test as the Nature of the Kernel is critical to running the system and security. They would have said nothing had greg and his team missed the code, and this would make that KERNEL version corrupt and a security Flaw.
This practice is one that always uses this excuse when causght, particularly by hackers trying to defend their actions in caught. Had this been windows Kernel, there would be a law suit. But open source can only really result in a BAN!
This was intentional, it was deliberate, and though it is conjecture for me to say it was deliberate, I believe 99% that these are guys working for some 3rd party goal, and possibly that 3rd party is China or the FBI/CIA trying to force their backdoors into software they cannot control due to it being open source.
In my opinion, and I use Linux, Greg is a Hero in his own way. When someone does his job to this level of detail, it is worth a medal. He has saved many uses from security breaches that could have been used to steal Identities etc...