i havent used bar soap in a good 10-12yrs always the liquid. I feel its a lot more sanitary, espcially if you have multiple people using the shower. never have to worry about find hairs in the soap, just nasty.
In My case it might just be beard hair and not that other hair.
You are worried about a hair in the soap and yet I'll bet you use the same toilet seat as others.
Do you also worry about the water droplets that get into the air from inside the toilet when you flush that could be landing on your toothbrush too? Do you remember to change your toothbrush on a regular basis to prevent bacteria build-Up.
I could go on and on ..... for example have you ever been in the back of your local supermarket and seen how the meat is handled? I have and I still eat it anyway. I've been in the back of 7-Elevens, QuickCheck, C-Town, Gristedes, FoodTown, Grand Union, A & P, Shop-Rite, Pathmark , Little Independents, Places making Hot Dogs, Italian bread and so on. Some of the chains aren't even around anymore, I manage to eat food anyway.
Best one was a Italian bakery in one on the Boros of New York City, The Driver of an open top truck was walking around on top of the "Day Old" bread getting it balanced from front to back. Turns out he was picking it up to be turned into bread crumbs.
Federal Regulations limit the amount of Insect parts in spices, They do not require insect free. Why do you think Flour gets buggy when it gets too old?
Ever been in the back of restaurants, I have I still took the free lunch.
Considering what we eat I'm not even close to worrying about did someone else in the family shed a hair in the bar of soap.