I think the highlighted is the whole point of the discussion.
People dispute that failing to or refusing to use someone's preferred pronouns is violence, because they think there is an important distinction being elided between, say, harassment and violence.
Those who think that failing to or refusing to use someone's preferred pronouns is violence have to argue that there is no meaningful distinction.
I know the difference between a shove and a shank in a kidney, even if they are both physical violence. (The existence of the common phrase 'physical violence' is a solid piece of evidence of the existence of other forms of violence by the way.) There is no reason to say that identifying two things as both 'violence' means there is no meaningful distinction.
Perhaps a better example is knowing the difference between a shove, and a
violent shove, even if both are technically 'violence'.
Yet when asked if violence should be met with violence, you argue that the first form of violence is very different to the second form of violence, which is selling the pass.
If there is a useful distinction to be made between two senses of a word (one of which is extremely controversial) then it makes no sense to muddy the waters by insisting that the word be used interchangably for vastly different situations.
I get what you're saying about weakening the meaning (and the hyperbole problem), but not only has that ship more or less sailed on 'violence', the inverse problem is also driving the dilution.
That is to say, people denying that misgendering is even rude, much less a meaningful problem, drive the rhetoric to more 'important and clear' phrases to communicate the actual impacts. Remember the push for the 'power plus' definitions of racism and sexism? Or old school (and still in use) definitions of 'rape' which exclude a lot of actual rape? Proponents of all of them claimed it wasn't to downplay other forms of racial bias, of sex based bias, or of sexual assault that was not being penetrated. In practice, each is used almost exclusively to downplay and dismiss instances of those things some groups found inconvenient.
Here is mostly the same thing. I can disagree with calling misgendering inherently 'violence' while both agreeing that it can be part of targeted harassment as bad as violence
and that people opposing the use of the label are mostly doing it to downplay the impact of misgendering. I can recognize that people pushing back saying it can be violence can be doing it in proxy of the argument over if it's wrong to misgender at all.