and you do some work but don't fix the problem, at least you've fed SOME concrete people.

Really not true at all. At least in the US, there aren't a lot of starving people down the street for you to feed.

If you work on fixing "the problem" of starving people, you can spend endless hours designing a "fix", organizing other people, "consciousness raising", fund raising, and organizing logistics without ever feeding a single person a single meal.

This means that unless you have large leverage on politics, the time you spend on it will simply be wasted.

Oh no. You'll gain power and connections with a group of people bent on power and connections. That's not a waste.