why does my internet access window list other users that are not connected to my wireless router but listed?

[Tony RB]

You want to know what other wireless users are nearby, because if there are a lot of them, it could interefere with your own network.

Wireless is radio and the different signals can interefere enough with each other that your router and wireless receiver in your computer can't make sense of the data they are receiving.

You already have WPA2 encryption enabled.

Look at the URL for this question; it begins with https

That means the entire webpage is encrypted. So even if someone was copying the data sent between your computer and the router, they can't make sense of it.

Most webpages do not use https as the encryption adds more work for their servers and thus slows down their servers.