"Where is the evidence to suggest the woman doing the insulting is gender critical?"
Indeed.
Whether the Toilet Video is staged or actually happened, the only rational reading of the situation is that the Bully is not female but is a man posing as a woman.
The Bully
The Bully says:
"I have gotten called out several times for being in the Men's Room, so you are going to be called out for whatever you're doing. So what are you identifying as today?"
Who is massively more likely to claim to "have gotten called out several times for being in the Men's Room"?
A woman, "GC" or otherwise, is not even going to have been using the Men's Room in the first place.
However, we hear time and time again from trans activists the claim that it is "dangerous" for TW (males identifying and/or attempting to present as women) to use The Gents as they are attacked or chased out.
This claim is contradicted by court reports and sightings, which almost all involve women being attacked in The Ladies (or more often in mixed-sex toilets) by men, whether claiming to be women themselves or not.
Meanwhile, verified accounts of TW being attacked in or chased out of The Gents are rare as hen's teeth.
So, faked scenario or "this actually happened", the role of the Bully is not taken by a "GC woman" but more likely by a man posing as a woman.
(It is not possible to know if this is a TW so, not wishing to be reported for the heinous crime of defaming TW, I have gone for the description "man posing as a woman". )
If this is faked then it is not possible to know whether they male, female, trans or otherwise - but if it is real then 100% what they are NOT is a "GC woman".
The Victim
The Victim is very obviously female, as can be seen from the follow-on videos on TikTok, although she possibly imagines that having a short haircut means she will be mistaken for a man or a boy?
In the "Toilet Video" her speech is weirdly stilted. It sounds like someone reading lines for a play but as that is implausible I am going for her trying to remember her lines or just really amateurish improvisation.
1 Video tweeted by Montgomerie www.tiktok.com/@creatingjayrose/video/715934312895519466
2 Follow-up video - very dark but voice is clear www.tiktok.com/@creatingjayrose/video/7159815373699829034
3 Follow-up video
www.tiktok.com/@creatingjayrose/video/7159825336815996206
4 Followup video
www.tiktok.com/@creatingjayrose/video/7160074728684735786
I went more into why this seems like it has been staged in an earlier post:
www.mumsnet.com/talk/womens_rights/4665955-cis-woman-harassed-in-womens-bathroom-by-a-gender-critical-woman-who-thinks-she-is-trans-she-is-upset-by-the-experience?page=3&reply=121122997
At that time I thought The Bully was just spouting gibberish with an outside chance that they were a man posing as a woman. On reflection, whether real or faked, the only way it does makes sense is if the The Bully is a man posing as a woman. So NOT a "GC woman".
There is still and outside chance is that it is a woman who makes a habit of choosing to go into The Gents for a pee (why???) and getting chased out and who has also bought in to all the identity bollocks wholesale. If so, she might be crazy but there is still ZERO chance this is a "GC woman".