The difference is, to access my unlocked doors/windows etc, you have to go onto my private property which I did not grant you permission to.
In the case of WiFi you are transmitting beyond your property onto your neighbors property and very likely public property, like the public street in this case. In addition the very airwaves that you are using are public and are not your private property to begin with.
If you want to use the public airwaves and expect any privacy it is your duty, and no one else’s, to encrypt your data.
If people talking in their house tend to shout you still aren’t allowed to record them even though the air being vibrated is public. this is the same, the vibration is just much higher frequency.
I don’t necessarily have to trespass to see you leaving your windows open, doors unlocked, putting a spare key under a garden gnome, what times you come and go, where you go, etc. Are you sure you wouldn’t mind if I compiled a database with all of your security information, and published it?