I think many of these arguments are just about the confusion between an in-the-system and out-of-the-system perspective.

Suppose I say "Joe Bloggs shouldn't be President". You could reply "Who are you to say that? We have a democratic system, and if the people choose to elect Joe Bloggs as President then Joe Bloggs should be President". And of course you'd be right in that I don't have the right to stand outside the system and declare that Joe Bloggs shouldn't be President. But if we zoom in on the democratic system then you'll see all sorts of people standing around arguing about whether Joe Bloggs should or should not be President, which is probably the level on which I meant to make my pronouncement in the first place.

Similarly, if I say "login" isn't a verb, it's not because I'm setting myself up as the independent arbiter of what is and isn't a word, I'm merely expressing a ground-level preference within-the-system preference that it should not be considered a verb (due, in this case, to inconsistency and the impossibility of sensibly putting it into past tense), and words come and go due to just such sorts of ground-level arguments.

So, with that out of the way, I agree that "login" shouldn't be a verb. Also, "panini" is plural and the singular is "panino".