That thread is disgusting and very disturbing. There's a bunch of troons relating to this image, talking about how they either have gotten caught or almost caught wearing their mother's or sister's clothes. Not one person is telling them that it's wrong to wear your mother or sister's clothes (especially their bras and underwear). No one is talking about how this crosses a boundary that is not appropriate, regardless if you're transgender or not.
It's bad enough to see adults encourage this nonsense, but it's more worrying to see young teens being taught that this is okay since they're "transgender" and just trying to live their authentic selves. Think of all the young lurkers in that thread that will now feel encouraged to raid their sister or mother's closet, now that they feel it's "okay" to do.
One commentor said that his mom let him borrow her bra after he came out. Wtf? What kind of mother would do that? Just buy him his own bra, ffs. I never wore my mother's bra and would have died of embarrassment if it had ever been suggested. Borrowing outerwear is one thing, but mom and daughters never share underwear or bras***
Slightly off topic, but I've never seen a post about FtM's talking about borrowing their brother's or father's clothes.
***Okay, one time I remember my friend had to borrow her mom's underwear, but that was only because their washer and dryer had broken the night before, and she had no choice. Even still, she was deeply embarrassed and hated it the entire time.