I think it comes down to at its greatest core: is there a reason and are the people affected on board. And I'll present 3 examples: transgender, differently abled, and latine

Back in the old days trans people were called transsexuals. Unfortunately that word had problems; it was a medical term, it's diagnostic criteria had problems to say the least, and the "sexual" component had people uncomfortable as it didn't have anything to do with sexuality. The community adopted a new term, and it spread, and eventually the old term became seen as outdated and like evidence that someone hadn't been around trans people since we started defining our own selves.

Differently abled came from abled people who were uncomfortable acknowledging that disability is defined by what we can't do. The social model of disability exists and bears quite a bit of merit, but the fact is it was just a platitude. It was rejected by the community it described. I don't hate it. Good try and whatnot, try asking some of us before coining a new term next time.

Latine is more controversial. It was coined by queer Spanish speakers looking to create a gender neutral grammatical gender for Spanish that doesn't have the jar of latinx or the unpronouncability of latin@ (which i recall had been coined as a feminist attempt to remove the neutral masculine). However many Spanish speakers don't want a neuter gender in their language and it developed some culture war bullshit, in part because queer non-spanish speakers picked it up fairly quickly especially after years of hate against latinx and because the Spanish speakers we're most in conversation with are the queer ones.

Oh and for a bonus one. Hearing impaired got popular as the politically correct version of hard of hearing in the late 20th century (idk when I grew up with my mom saying both terms but my grandma said hard of hearing, but schools and audiologists said hearing impaired). Anyways the deaf fucking hate the term and it's become a clear identifier that someone sees deafness as a medical thing entirely and not a community and a culture. This has lead to the idea that while hearing impaired is the politically correct term, hard of hearing is the culturally correct term, which is a distinction I quite like

At the end of the day it's about manners and putting forth a reasonable effort to make others feel welcome and comfortable.

Prescriptions and descriptions are not opposites. They're orthogonal to each other:

• when you tell people how things are, you're being descriptive;
• when you tell people how things should be, or what they should do, you're being prescriptive.

And prescribing is not automatically wrong. For example if I were to tell someone "don't call us Latin Americans «spic niggers», it's offensive", I am prescribing against the usage of the expression "spic nigger"; it is prescriptivism. Just like when someone proposes inclusive language.

What is wrong is that sort of poorly grounded prescription that usually boils down to "don't you dare to use language in a different way than I do, or that people did in the past". It's as much of a prescription as the above, but instead of including people it's excluding them.

Tagging @bgainor@thelemmy.club, as this addresses some things that they said.

Using inclusive language isn't linguistic prescriptivism. Prescriptivism is saying "this word is incorrect English/doesn't mean what you are using it for." Inclusive language is saying "if you use this word, you're being a jerk."