I don’t know if anyone remembers the movie Inside Man where at the beginning they are waiting in line at the bank and the woman is having a loud conversation on her phone and the guard comes and tells here to keep it down. It’s this kind of person that I see not using speakers (when the movie was made I don’t think they contemplated humanity could sink that low), at best it’s entitlement, but I still think in most cases it boils down to not thinking about others vs actively trying to annoy them.

I’m sure it is, much of the time. But I also believe many people are just completely self absorbed and devoid of empathy.

Hanlon's razor applies. Yes, some people have a bad case of the main character syndrome simply because nobody has ever called them out on it.

A lot of people don’t get a lot of things; you know the adage about stupidity being a more likely cause than malice. Just last week I had to explain to a grown adult why spitting on the sauna floor was disgusting and rude to the other gym members. He was shocked.

It's apathy

I experienced this in real life and this creature was unable to understand the bus driver telling her to stop. It's like they didn't understand English nor social signals. To me it seemed to stem from a lack of intelligence than from intentionally being malicious.

Sorry to disagree -- stupidity and self-centeredness have a plan in that too.