This. In many many places you see people like that. Many NGOs and charities don't help solving the problems at all if not aggravating them. It makes me doubt if the people running them are actual well intentioned people or just selfish in a different way.
It is rarely, if ever, about feeling nice about yourself. In fact charity work generally demands being confronted daily with what you like least about the world. My personal experience working for an environmental NGO is that, while not entirely thankless, it is exhausting and often depressing work.
Our charity is one of the many asking individuals to take small actions in their daily lives. It's a small request and direct outcomes are difficult if not impossible to measure, however our org has been directly involved in any number of environmental policy changes across the many businesses and even cities that we work with. These efforts bubble up. From little things big things grow.
The many people bit is problematic due to our brain's make-up.