Getting banned from contributing is a light penalty.
It is pretty comfortably not sabotage under 18 USC 105, which requires proving intent to harm the national defense of the United States. Absent finding an email from one of the researchers saying "this use-after-free is gonna fuck up the tankz," intent would otherwise be nearly impossible to prove.
Presumably, this reference is intended to be to 18 USC ch. 105 (18 USC §§ 2151-2156). However, the characterization of required intent is inaccurate; the most relevant provision (18 USC § 2154) doesn’t require intent if the defendant has “reason to believe that his act may injure, interfere with, or obstruct the United States or any associate nation in preparing for or carrying on the war or defense activities” (emphasis added) during either a war or declared national emergency.
It wouldn’t take much more than showing evidence that the defendant was aware (or even was in a position likely to be exposed to information that would make him aware) that Linux is used somewhere in the defense and national security establishment to support the mental state aspect of the offense.
There is absolutely zero evidence of this. None. In my opinion it's baseless speculation.
It's far more likely that they are upset over being called out, and are out of touch with regards as to what is ethical testing.
From TFA: “The UMN had worked on a research paper dubbed "On the Feasibility of Stealthily Introducing Vulnerabilities in Open-Source Software via Hypocrite Commits". Obviously, the "Open-Source Software" (OSS) here is indicating the Linux kernel and the University had stealthily introduced Use-After-Free (UAF) vulnerability to test the susceptibility of Linux.”
Suggesting a foreign government could be leaping to conclusions as well, given domestic activists with an agenda may do the same thing. A linux kernel backdoor is valuable to a lot of different interests. Hence why counter-intelligence should be involved.
However, I just looked at the names of the people involved and I don't know. Even if they were Taiwanese, that's an allied country, so I wouldn't expect it. Who were you thinking of?
Talk about predictive power in a hypothesis.