> I certainly don't interpret "keep your circle of concern as small as possible to your circle of influence" as "stop giving a crap". I actually means that you for example should decrease the amount of meat you eat and try to find other means of transportation than car if possible.

Exactly—before trying to solve the world's problems (and getting frustrated because you can't), try to solve the problems closer to home (and get motivated because, if you keep your focus small enough, you can).