I get that. I don't condone the behavior of those doing the fingerprinting. But what I'm saying is that the fact that it is possible to fingerprint should in pretty much all cases be viewed as a sort of vulnerability.

It isn't necessarily a critical vulnerability. But it is a problem on some level nonetheless. To the extent possible you should not be leaking information that you did not intend to share.

A protocol that can be fingerprinted is similar to a water pipe with a pinhole leak. It still works, it isn't (necessarily) catastrophic, but it definitely would be better if it wasn't leaking.