Software is complex. Wasting maintainer's time is harmful to the maintainers and to those who use the software. If the goal is to explain what sort of exploits to be on the look-out for, just write the paper without doing the exploits.
As for the letter, their goal is to recover their reputations, not to apologize. I suppose a lawyer helped them in spots, but there is still a certain truth that shines through: they want to continue on doing this sort of thing, because they are oh-so-clever and their work is oh-so-valuable. Nice try, but the academic community may be better off without these folks doing this sort of research and influencing students to follow their methods.
[signed personally, by every involved researcher, professor, IRB member, and all of the relevant university leadership including the board]
Something like that would do nicely, in my opinion. Then they'd have to absolutely follow through on it. Ideally, they'd also ask involved members of the community so harmed, among other experts, to independently review and watch the process to ensure no further harm is being done, progress is made, and public accountability is kept.
I wouldn't trust those researchers again, not for anything. Free software depends heavily on trust. It's astonishing that it works so well; but if you break trust, it's very hard to repair the fractures.
The legal arrangements around free software are fairly fluid, because there hasn't been much case-law, because there's not much money sloshing around for Free Software developers to pay lawyers. Banning pull-requests from that college is much cheaper than sueing.
I hope the whole uni stays banned until the ethics board issues their own apology.
Then let it go, I say. People make mistakes. We shouldn't blame everyone for the mistakes of a few.
But we have to protect the Linux kernel; billions of people depend on it's correctness.
This bit just reads like "sorry you're upset".
I would have expected something along the lines of "sorry, we should have asked the maintainers and we understand why it was wrong not to", instead of "sorry, we didn't ask the maintainers, but this is why we didn't".
Legitimately these folks have some kind of personality defect. They observed something that everyone already knew and then decided to act on it and pretend they were doing something interesting and new rather than just being twats. They should be treated exactly as should be based on their actions, regardless of their claims of being researchers. This would be a perfect cover for being on the take from a government agency. They should be investigated to ensure they aren't actual malicious actors.
It takes almost no imagination to think of hundreds of "security vulnerabilities" in the world, yet the vast majority of people realize that it's dumb to act on those observations.
While I had a bunch of notes about what makes the sentiment behing an apology meaningful, it's really separate from the issue that this should have been done privately. A public apology is just another thing about them and their message. They're performing and trying to draw in sympathetic members of an imaginary audience. There is no humility in public displays. I would be surprised if anybody asked for it, and doing it without asking is just more of the same type of behavior. There is no such thing as a public apology.
That said, I have no doubt they have suffered personally over this, and have some compassion for that suffering itself, but not sympathy for this performance. There is no gesture that restores trust. When their contributions and acomplishments become more remarkable than this issue, they will have restored it, but like most things, there is no "back" to go to. Maybe that static analyzer will be the ultimate bug finder, as succeeding at that is probably their only out.
You seem to be implying that one apology is as good as another and that is absolutely not true. To me is is absolutely unfair to expect that people will treat a zero effort "sorry your feelings were hurt" apology the same as a deeply heartfelt apology by someone who feels deep remorse.
By it's nature, an apology should be an act of making amends to a person your have wronged. If the words of your apology don't do that, you have failed, even if you had good intentions.
If the author of the apology isn't a native speaker of english, this seems like a document of sufficient significance to merit asking a friend or colleague for a proofread. (Which you should do in a case like this even if English is your first language.)
The core issue here is that the system under which they were working, and the researchers themselves, did not consider this work to amount to unethical human experimentation - even though the work directly involved infiltrating and exploiting humans and human social systems. There is no mention of this nor of any substantial desire to understand or address this systemic failing and, until there is an unconditional acceptance of responsibility for the harm caused and a real actionable change for the better with accountability, I don't see how we can consider this matter to have been apologised for.