I have long hair and it does shed in the bathroom, especially when I wash it, but I always make sure to clean it all away so that there is not a single hair left in the shower and I am careful not to let it get in the drain. In fact, a bathroom alwasys looks cleaner after I've used it than it did before! I'm not OCD, I just understand that other people do not want to shower with my hair. It really doesn't take much effort and has become such a routine that it's the same when I have a bathroom all to myself, e.g. when I stay at a hotel.
However, I find that many guests do not think twice about leaving the shower covered in hairs, especially a load of it blocking the drain. Guests leave the bathtub covered in stubble. Worst are the ones who leave the shower or bath covered in pubic hair. Aren't they embarrassed to do this knowing someone else is going to see that? It's gross to clean up, but with bathrooms shared between different guests, it's just something I have to do.
It would really annoy me though if guests were complaining about the hair they left themselves. That's pretty unreasonable. @Kelmany0 are they expecting you to camp outside the bathroom so that you can clean up after them every time they use it? You don't even get that in a 5 star hotel whre you are paying way more. You get housekeeping once a day and that's it.