Why do people think it's impossible for clean houses to have cockroaches

Example:

Person #1: I saw a cockroach in my house.

Person #2: That must mean your house is filthy, because that's the only explanation for why any structure would have even a single cockroach inside of it.

Roaches are like Seinfeld. They clean and groom themselves fastidiously. They are looking for food, not for filthy surroundings. Therefore it is perfectly possible for a fastidiously clean person to have cockroaches.

If you live in an apartment surrounded by other people, cockroaches are inescapable. If you live in a detached house, you should not have cockroaches or very few. Houses usually have spiders, tiny centipedes, ants and other tiny insects from the yard. Few if any cockroaches. Regardless, just get some insect spray.

They simply do not want to believe that their nice, expensive, suburban can be infiltrated by anything unpleasant- seemingly.