I just get a chill at the thought of some of the predators (not genuinely trans people, but rather predators cynically exploiting self-ID) who will end up in women's dorms.
A few years ago I had a very disturbing conversation with my nephew. Nephew was (horribly) subject to child sexual abuse at the age of about 10 or 11 (the sort of "trusted adult on the fringe of the parents' circle of acquaintances" form of CSA) - not enough proof to prosecute (which is infuriating but not exactly a surprise to anyone on here, I guess). Nephew (now an adult) and I were chatting on the phone one evening, and he mentioned how he had, years later, come across this man in a youth hostel dorm!
Now it is of course beyond horrible that this sort of predator can gain easy access to male victims... but to double the number of potential victims by allowing them into women's dorms as well just beggars belief. Also, my nephew's experience gives the total lie to the idea that everyone you encounter in a youth hostel will be a nice wholesome individual.
(Incidentally I am beyond furious at the twat upthread who said we should just not go hostelling. Where do they draw the line? As another poster said, should we sit at home in self-imposed purdah? If I'm going to be asleep and vulnerable, I want the space where I'm asleep and vulnerable to be single sex not mixed.)