Also, trans women are easy to spot which is why not disclosing their non-cis status is rape:
Also, according to “gender critical” TERFlogic, feminist discourse is describing the vaginas of trans women in the way anti-feminists discuss the vaginas of cis women.
But then, these Reddit TERFs are merely aping the public behavior of TERF opinion leaders:
To punctuate the ideological differences between patriarchy dressed up as Radical Feminism – TERF ideology – and actual Radical Feminism, here’s what Andrea Dworkin had to say about the type of discourse TERFs and anit-feminists use:
Women are also wittily rebuked for having filthy genitals… The filth of women is a central conceit in culture: taken to be a fact; noted, remarked on, explicated, analyzed… excremental filth, filth down there, between the legs, in the hole, the wound oozing blood and slime, dirt and smell; the dirt inherent in the genitals or in her bad character 
Linda Shanko (AKA “Gallus Mag”), the proprietor of the popular TERF site known as GenderTrender – a site that functioned as source-material for Jeffreys’ newly published academic book Gender Hurts  – took a turn at disparaging the vaginas of trans women. “Some of Bower’s clients have…’complications’ from the procedure which turns penile material into a fuck-hole [of] chronic UTIs and odor/infections.”  Shanko wasn’t alone in her mockery of the bodies of trans women. Commenting on one of Shanko’s posts, a reader replied, “Because surgical fuckholes are not vaginas… stale urine, lint, sweat, and body fluids can just get in there and fester. It’s totally nasty that anyone in their right mind would do that to their healthy body.”
Jeffreys had a great deal more to say about the uncleanliness of trans women’s vaginas. “The medical evidence is that a bad smell exists and is associated with fecal bacteria common to those male-bodied transgenders who engage in ‘heterosexual’ coitus.” Jeffreys continues, “The neovaginas lack the lactobacilii connected with vaginal health in females.”
While when actual researchers compared the vaginas of trans women to cis women, they concluded that a trans woman’s vaginal bacteria is similar to the vsaginal bacteria of premenstrual cis females , TERFs seem happy to take up a patriarchal discursive practices Dworkin explicitly despised and rejected. To have a woman’s vagina assessed – or, as Dworkin said, “noted, remarked on, explicated, analyzed” – to authenticate her credibility, legitimacy, and validity is to deploy the very patriarchy TERFs (ironically) assert their “gender critical feminism” fights in their decades-old war on trans people. Andrea Dworkin, Intercourse, p 233  Cathy Brennan outs Gallus Mag: http://i.imgur.com/9Y8pkfZ.png  Sheila Jeffreys, Gender Hurts, p viii  http://archive.is/Ykr3Q  http://archive.is/FZKJl  Weyers S. et al., Microflora of the penile skin-lined neovagina of transsexual women, BioMed Central Microbiol 9, 102 (2009)