Sometimes I will invite USian people into my home and they simply walk past the threshold without thinking, shoes on, not then washing their hands, parading their dirty un-bideted ass everywhere
This is a regional thing within the us, too. We don't do house sandals, but there are places where people look at me like i'm from mars when i take my shoes off at the door. Then i look at their carpetted floors and try to poker-face my look of abject disgust.
Carpets in the US are designed so that they actually improve when you smear dog shit residue between their fibers. That's how you break them in, they get soft and comfy that way.
Someone should add a fake subtitle
Yukari-sensei, in America they don't have public healthcare right?
Then, what if they got sick but don't have money
I found a YouTube link in your post. Here are links to the same video on alternative frontends that protect your privacy:
parading their dirty un-bideted ass everywhere
designated shitting shorts