@truepurple
So, suppose you're one of those girls in a job interview. It works the same way as looking for volunteers. Do you think there's any employer who will hire you? Duh, no way. Why?
The first girl: She doesn't look serious about it like if you give her a chance, she'll drop it any minute.
Second girl: She sounds like mocking her own grandpa, which makes you think she might be secretly mocking deaf/hearing impaired people in general.
Third girl: Asking for payment details right off the bat despite knowing it's a volunteer work. Srly?
Fourth girl: She sounds sincere at first but has ulterior motive and it's not to rape him per se but to seduce him. (why are you jumping to conclusions that it's rape? lol)
Lastly, it's not being sexist. If those girls were guys, Kouhei most definitely would be in trouble he has to turn them down right away. I mean he just wants a little help! They should've showed delicacy at the least, if not ethics.
I hope this makes sense like I'm already stating the obvious here.