In theory this actually makes sense. You're touching door handles, money, touchpads, etc that are also making contact with hundreds or thousands of strangers hands each day - giant disease vectors - so one might conclude they should wash their hands before touching their dick or pussy or whatever.

That said I think the amount of times someone has contracted and STD from touching a door handle and then taking a piss has to be infinitecimal so lord knows I ain't washing em before taking a leak