there is a very large inferential gap here i think but im gonna try and gesture at what i mean i think. i wrote this while mildly delirious and im not super sure i endorse it, but here we go, put under a readmore for length and like, frank and very mildly outside-viewish descriptions of transphobia
i think the linguistic aspect, pronouns and such, the idea of wanting certain terms to be used that came up in posts i was thinking of when responding here, is better thought of as a meta level dispute than an object level one. that is, the reason this is under contention, is not a fully free floating preference for terminology here, rather, its about what is being expressed by the use of gendered terminology. in this sense, i do not think its fundamentally a different kind of fight than ie, about the acceptability of homosexuality, the linguistic angle seems like a red herring
so, what is expressed by gendering someone? well obviously, people will make different claims of varying degrees of plausibility as to how they might define a gender, but well, i dont think i have a verbal definition of man or woman (or nonbinariness beyond negation of the former two), but i would say, gender is a real attribute someone can have which is not unrelated to all sorts of things we can say about them, and predictions we can make about them, and that trans people are not exceptions to this. that is gendering someone is a meaningful descriptive, not just normative(?), claim. this can include like, anything from how they act, to what they are like as people, to what their bodies are like, to how other people and social structures treat them, to what established social role in society they occupy, to what sort of things they might wish to do in relation to their gender, to what their appearance is, to like, yes, what their psychological relationship is to gender identity.
it is in this sort of sense that misgendering can be incorrect, that its making a false statement about someone. i dont think my disagreement with transphobes is purely something where i think we should draw lines, i think transphobes are wrong about trans people. one way they are wrong is in having, well, a fairly incoherent attempt to define gender (generally claimed to be about biology, but really more like a permanant metaphysical tag they imagine which is quite detached from it), but also they are wrong in other ways along the lines i mentioned, they imagine things about trans people that are not true. maybe the easiest thing here to point to is how transphobes seem frequently ignorant of how hrt works, but there are a lot of things here - consider how common it is to ie attribute predatory attitudes to trans women that are said to be characteristically male, or how people make up false theories of gender "etiology" like autogynephilia or social contagion/ROGD stuff, or how they seem to want to deny examples of trans woman being treated like women by patriarchy, or even just wanting to maximally exaggeratedly insist someone looks unlike their gender, etc. but at a smaller more individual scale, theres really a lot here but its hard to express, it seems transphobes want to consistently claim trans people are unlike their gender, in any given way, and they are often wrong about this! so like, ok honestly im not sure this is the best way to describe things or really all the phenomenon. but this often means, transphobes are wrong about trans people, in difficult to elaborate but real ways, and this is relevant to what they are expressing when they misgender someone.
(some may argue there is also more here in terms of like, intersex neurology or even metaphysics, and i have sympathies in that direction, but for our purposes i think we can treat these as hypotheses of additional features of gender rather than its definition which is probably? in line with my views on those possibilities myself)
so, theres another thing that can be expressed here, which is political or assertive, its saying "yes we are going to treat this person as [gender]" this is the second thing that seems relevant here. it is, obviously, also an important one. and can include like, references to real actions someone plans to take or think should happen. this is another way it matters. this is i think most obvious looking at transphobes - its clear that misgendering is often done with deliberate effort and with spite.
but things can i think go a bit off the rails here, when focused exclusively on the idea of assertions of inclusion or exclusion. what i mean by that is, looking at this part, especially when emphasizing social roles or identity in the prior, there is a tendency to end up treating gender solely as a category that is quite free floating, even from any particular consequence of action. this tendency is very strong among like, well meaning cis liberals, and is related to the whole implicit "transness is a delusion im humoring" attitude some of the more obnoxious stuff in that direction can sometimes fall into. or see also "using AFAB and AMAB so as to include trans people, but then using that to say stuff which is just transphobic false assertion of alignment with assigned gender". and a lot of "debate" gets, i think, warped around this direction.
and i think from there, its quite easy to end treating the whole thing as about language or pronouns, instead of treating language or pronouns as expressions of something. this ends up plaguing a lot of how people talk about transness imo!
but i think the first thing, and the second if you stay grounded… these are not "about language", i think they are not qualitatively different from other kinds of arguments that may be had. its not, i think, a particular feature of them that they are about asking for particular language, because the language is meta - its an expression of the real underlying dispute, and the reason the language most matters is because it may a) express claims that may be true or false or b) an intent or sentiment which can be benevolent or malicious