why does everyone think it's ok to touch a baby's mouth!?

Like wtf. Seriously. I'm livid right now because I've made it my life goal to keep my daughter healthy this winter. She's now 7 weeks old and has already gotten a cold which was miserable for both of us... we've had multiple visitors come over and touch all over her face, and even put their nasty hands on her lips/mouth!!!! Like on what planet is this ok!?!? I didn't think it as necessary to tell visitors "ok please don't touch the baby's face or mouth" before they hold her... does anyone else have issues with this? Has anyone found any nice ways of asking people to be careful of germs? The first month we asked people to wash before holding her but repeat visitors I just thought would know... apparently not 😫