I find Gandhi's response to cynicism (& yours, via volunteering) one that--if nothing else--removes the negative weight of cynicism from me while I'm engaged.

I work with shelter animals. Other things I tried only kindled my cynicism after a while. I work especially with the older & frightened ones who have less & less chance of adoption as time goes on. A lot go on to find homes.

I may never do any work directly involving people. People say I waste my time on animals. I carry earplugs when I leave home now. I'm so sick of what people say.