1. Your opponents are going to give a pass on hypocrisy from people on their side that they won't give to people on your side. That's because they don't want to blunt their own sword.
2. Not every political action is motivated by money, greed or capitalism. People derive plenty of motivation from hubris, ego, and nationalism as well.
3. Government hasn't failed to address your concerns simply because of "special interests." Democratic government is consensus-based, and is very tough to get sweeping changes through.
4. It's not shocking that people care more about things happening in their own lives than all the numerous tragedies going on in the world. If they did everyone would be a quivering little ball of misery.
5. If you care deeply about issue x and want to advocate for it, you're going to spend most of your life convincing people who are completely apathetic or oblivious that they should find your thing more important than the thousands of other issues out there. You will fail 99.9% of the time. Enjoy!
I swear if you can internalize this, the world will make more sense.