So many of then keep saying 'we are a community", “our little community” and so on. Who is this “community”?, the country?, the state?, the town? Politicians love saying for 'the community" and “us the community” like it’s some kind of buzzword. I think this is just some tribal mentality of us versus them.
It’s kind of like asking British people why they use the word “boffin” to refer to scientists and engineers. People use the words the people around them use, so it’s just normal to them.
I must admit, however, as someone who is not American, that I do feel a certain …discomfort with the way they use the word “community” that I don’t feel with most other Americanisms. It’s kind of similar to how I’m wary of American things with the word “family” in the name (family values, Family Radio etc.), it feels like there’s something sinister behind the choice of the word, even though there’s nothing wrong with the word itself. So it would be interesting to find out whether there is, or it’s just something like a remnant of most Americans living in small settlements being relatively recent history, but it would probably take a historical linguist to answer it.