Nothing particularly special or more dangerous about them than anything else.
Actually there are differences. Shopping carts get kids will loaded diapers and parents who just changed loaded diapers but who failed to wash properly.
Outside surfaces which get exposure to sunlight aren’t much of a worry since the UV will kill most of the bacteria which can harm us.
Certainly some people take it too far but to say there’s no reason to be concerned with these bugs is just ignorant.