It's stealing and it is wrong. Relatively minor, however.

I don't believe everyone who's got an open wi-fi is doing so intentionally. They hardly sell routers without wif-fi nowadays. People walk in to a store, buy a router, hook it up, get it working and then pay no more attention. They don't know or don't even think about the fact that their neighbors may start mooching. We here at this forum are quite different from the average person.

And for some people bandwidth can be a finite monthly resource.

CR