but don't you understand that exposure to germs builds a good immune system?
Yes and no. Exposure to measles, for example, wipes out about two years of immune memory from a child, thus negating everything they've been exposed to and built up defence against (vaccinate your kids, folks.)
I'm happy to let kids get mucky, roll around in the garden, eat worms, play with the cat/dog, etc. that sort of stuff helps their immune system. I don't use antibacterial stuff (pointless) and I don't consider myself particularly tidy.
But I've worked in enough labs to know that an infection in one cell culture can transmit via the tiniest, tiniest bit of contact. I have a healthy respect for our little microscopic friends. They're tenacious and amazingly successful. Bring me your mucky paws and let me press them onto my Petri dish ..... I'll show you exactly whats a-lurking on them!
Hands need to be washed after toilet, nappies and before food prep. I wash mine when I come in from being outside and we take our shoes off in the hallway (standard Swedish behaviour.) shoes in the house here is considered dirty.
No ones suggesting bathing in dettol here, just very basic hand hygiene. Soap, water, good scrub.
Doubly important around tiny babies, patients in hospital, care settings etc. Christ knows how many deaths a year are due to crap hand hygiene.
Wash your hands, people!