Because these people are incels. Or well, what the internet calls incells. Actually they are able to change their celibacy status so there's nothing involuntary about it, they just choose to be shitty people nobody wants to sleep with. That's the problem both before and after transition. Just the transition adds even more baggage that further limits their dating pool.

Anyone going about dating with a "you must date me or else you are a bad person" attitude is not going to get dates. Simple as that. Before transition it's shit like "those assholes care too much about appearance" "those assholes are so selfish they only care about themselves" to deflect away from their own problems of poor hygiene and unrecognized and untreated borderline personality disorders.