I think there can be a lot of ignorance around germs in terms of the things you mention but also, increasingly, a view that we need as much germs as possible to "build our/our children's immune systems" and that you can be "too clean".
I've got one relative who won't let anyone touch her 17 month old's hands ( she gets furious if the baby reaches for your hand and expects you to bat him away even if she's seen you thoroughly wash and antibac your hands the moment you walked through her door) and mostly hasn't let anyone but her hold him. If her DH handed the baby to someone, she'd snatch him back in seconds. He can't stand or walk unaided and is rarely allowed to crawl because she believes most floors are contaminated. So he's spent all of his life in her arms. She won't even let him use a high chair when we're out. There's the very clear message that other people are germ ridden fleabags out to infect her child. Never mind that we've all picked up numerous illnesses from him and her as she constantly takes him places he doesn't need to be when he's full of something nasty (i.e my house for coffee, afternoon tea at The Landmark, the hospital to visit a sick, elderly relative). Because everyone else is dirty. But not her or her baby who needs so much protection from other people.
To be fair she was like this before children. She'd invite people round for fancy NYE parties or candlelight dinner parties and seethe for days if her SIL hadn't psychically realised she was supposed to remove her party shoes at the door and "now she's trod dog shit all through my house". The woman has laminate floors throughout the house, and her SIL isn't in the habit of walking through the dog park in her rhinestoned, immaculate Louboutins. I mean, don't invite people to a fancy party in your house if you expect them (tell them) to "dress to impress in something sparkly" and then become apoplectic with rage if they dare to wear a shoe with their cocktail gown.
Yet. This same woman.
Lets her child suck on EVERYTHING on his bi-weekly trips to soft play and also in the play area at the doctors or urgent care/a&e.
Lets the child pick up and suck on vases, salt and pepper shakers, condiment bottles, chew on artificial flowers etc in restaurants and cafes.
Will let him drop his dummy/teething ring/toy that goes straight in his mouth on the floor, leave it there for up to twenty minutes and then not clean it all and pop whatever it was straight back in his mouth. I've seen her do this waiting outside the toilet at Costa and actually in the Dog Park whilst walking by a lake where the ground was covered in duck shit.
Or she'll be ill and she or another relative will suck his dummy and put it in his mouth. Or she'll stick her own unwashed hand in his mouth for him to suck on.
He regularly uses her phone as a teething ring...to the point that she actually hands it to him to use as such. Or her car fob and key rings.
She also changes his nappies, without a mat, on the seat or table of a fancy restaurant or cafe and leave the dirty nappy on the seat rolled up but not wrapped in a bag until she leaves and we/other diners are just expected to sit there and ignore the smell/awful hygiene of having a pissy shitty nappy on the empty seat next to you. I honestly wanted to disown her after those episodes. Oh...and she didn't wash her hands afterwards...went on to eat and drink and ask if we want her to pour more wine into our glasses which she would have had to pick up.
And she constantly moans about how the child and her are constantly ill and picking up Hand Foot and Mouth, Impetigo, Noro, Covid etc when they are "so careful and you know I'm a germaphobe and my house is immaculate".
Then blames it on MIL who let him hold her hand when he grabbed it or some old dear who stuck a fiver in his pram at her church. Because everyone else is filthy, especially old dears.
I mean...where is the common sense?