After pursuing the meaning of this through the internet for better than an hour, I have come up with this explanation. Some individuals, who Arnold Schwarzenegger might term as "lady-boys", and who have male chromosomes and male genitals, want to use female toilets. Also women's sleeping areas and women's prisons. The reason for this is that they believe gender is social. They say anyone who does not agree with them is trying to deprive them of their rights, and is filled with "hate and exclusion".

They loathe women almost as much as they loathe their own bodies, and as a result of believing they have become women, they spend a lot of time on "men's rights" forums trying to enforce strict gender roles and telling women how to act as women. I'm sure I have missed some nuance of this, and that someone will come by and set me straight on some of the detail, but this is definitely a thing. Anyone who resists strict gender roles is deemed a "terf", as in "kill terfs", which according to the New Yorker article, has become a common internet threat.

The two terms mentioned by the OP as being "widely recognized slurs" are no such thing, but we can certainly add all of these terms to those that do not belong on the talk pages of Wikipedia. That this term was used by an IP, and not a signed-in user, kind of speaks for itself.