It may have had to do with that, but it was also about strategies for getting to sleep with cis women/cis lesbians. That's literally the etymology of the term, comparison to the historical "glass ceiling" women face in terms of pay and promotion equality. The term was extrapolated to "cotton ceiling" for trans women seeking cis women, because they...felt...it was a similar struggle.

It's not.

And yes, most well adjusted trans women off the internet would be confused and probably wouldn't know the term.

But the too-online ones do. The ones who maybe ten years ago were edgelord 4chan basement dwellers before discovering sissy hypno, bimbofication, and "titty skittles"

I'm going to make it very clear to you and not mince words: the latter, heterosexual incels, should not be the beneficiaries of decades of genuine activism.