It does sound like they are careless but you also sound a little reactive. The thinking I see in your post goes like this:

1. a thing is either wholly corrupted or wholly pure
2. corrruption spread from whole thing to home thing by touch

It’s kind of a “cooties” mentality. The trash can? Wholly corrupted! It’s trash! And it touched the table now so the table is wholly corrupted! The table is where you eat!! It’s exactly the same thing as eating trash!!

It’s not. Truth is that the ideal is somewhere between sterility and filth. Sterility is not healthy to grow up in, nor is filth. Sterility may be preferable to filth, but that doesn’t make it ideal.

How clean does a thing actually need to be? This is always my question. Am I serving my soaghetti straight onto the tabletop? No, it’s on a plate. So do I care if something touches the edge of the table? No.

Spare yourself the anxiety of pursuing an ideal that isn’t even healthy.