People are so phobic about public restrooms that they believe if their butt cheeks touch the seat where someone else's butt toches the seat, they will get a horrible communicable disease. This leads to people squatting over the toliet, which leads to dirty toliet seats which made "toliet seats are dirty" into a self fulfilling prophecy. As a guy who used to clean public toliets, this bothers me. Women's restrooms are far worse about this than men's restrooms paradoxically because women are more concerned with hygeine and cleaniliness ergo they avoid sitting on toliets and mess up the seats. Note that in most of China, it's assumed that everyone should squat over the toliet and they really are too foul to touch with your butt cheeks. Especially in rural areas without much plumbing. A lot of bathrooms are basically little more than everyone going in a giant hole. There is an industry based on septic services where the ahem contents of these holes are vaccumed up and hauled away. Sadly, most day-to-day services (though apparently the bus service is very efficient) in China are understaffed and underfunded, so some of these holes overflow. Because elderly people often have trouble maintaining a squat, in China, you may notice some older people carrying around foldable personal toliet seats usable only by them. Fun fact, McDonalds franchise agreements requires every franchise to maintain their restrooms up to a very specfic code world wide. If you want western style flushing toliets with reasonably clean seats in China, your best bet besides a facilities in very rich neighborhoods is a McDonalds restaurants.
I agree that it can be taken to neurotic degrees in a sanitary environment, but it's grounded in fairly reasonable survival logic. It's one thing to go bare-skin in your house where you have a reasonable idea as to what you or your family have; it's another to do it in a place where you might not know if and what the last user was carrying. I've legitimately gotten into the habit of wiping down the seat, followed by putting a layer of toilet paper between the seat and my butt cheeks, for this reason, even if I know it gets sanitized with industrial-strength cleaner on a daily basis. Granted, it's kind of a necessary measure when said public toilet is on a warship, since squatting is not exactly a stable position to be in when experiencing Sea State 6.