You said this, "When I went to the office, I tried to go in and out of the restroom as fast as possible, touching as few things as possible"

which really comes across as you work in a disgusting place, or you might have a bit of an overreaction

Brush your teeth three, four or as many times as you like! As I said, beyond the minimum it's just a cultural habit. I knew one person who wouldn't consider her tooth-brushing complete if she didn't also brush her tongue, then removed "stuff" from her inner cheeks with a spoon... each time. (It's not a common practice, before you ask). She wasn't a dentist or a doctor either, I think she was a school teacher.

The overreaction thing is just your own baggage. Seems like a lot to extrapolate from so few words.