The kernel community isn't a spurned lover or anything; the apology just has to admit fault, promise not to do that again and be truthful about it.

There is no need for the researchers to be in any specific state of mind or even apologetic as long as they don't try to submit bad faith patches again.

Really the only reason there is even a need for a public apology is to signal how much pressure they are under so other people think twice before doing the same silly thing. Otherwise they could just apologise to the maintainers directly.