I know you have no idea about this, but women looking for period pants don't want to read a pervert's story about how he gets off on them.
First of all, as far as sexual fetishes go, wearing women's clothes and urinating into them is a really mild and vanilla one. There seems to be a lot of anger over this, and I'm not sure why. There's certainly no evidence that he's urinating himself in public, and no evidence that he's urinating on any else's clothing; just his own.
The second point is that I think a lot of people are reading stuff into this, which is why calling him a "pervert" is a tad extreme. We know he is a cross-dressing man, and we know he sometimes wets himself. However, he hasn't indicated this is a sexual thing (there is no mention of sexual arousal, or sex, anywhere in the review). Even if the cross dressing is a sexual thing for him, he hasn't indicated that wetting himself is part of the fetish- he might actually genuinely be incontinent.
I am a bit surprised that M&S would allow a review like this, but I don't find it to be particularly extreme or upsetting.
It's amazing how people supporting the ideology can end up defending rapists, sex offenders in spas, and perverts. And yet still think that they might be on the right side of history.
That's not true. I would never support someone imposing their fetish onto others, and I would never support a rapist, pervert, or sex offender in a spa.