Why wouldn't they? if being withing a specific social construct makes you uncomfortable best thing to do is to change the social construct.

i'm not really here representing a viewpoint other than "if someone wants to identify in a way that makes them happy, they should be allowed to, regardless of the basis they claim for it"

i specifically asked in this case because, especially nonbinary people, but also gnc trans people are sometimes invalidated because of the biological argument, so i wanted clarity on the commenter's position. of course, i don't know everything, and consider my experience to be fairly gender normative for a trans person, so i'm open to learning something new, as well

A common anti-trans response would be: if gender is a social construct, then perhaps people are influenced by social media into becoming trans. This is the debunked notion of "social contagion", it assumes gender identity is subject to social influence.