To take advantage of professional specialization, gains from trade, capital infrastructure, comparative advantage, and economies of scale, the way grownups do it when they actually care, I'd say that the activist is the one who pays someone else to clean up the river.

If people don't realise that the river is dirty and that's causing problems, changing that is valuable work by itself.

The more I read this quote the more I hate it. It is an anti-rationality quote. It says, if you are not rich enough to run as an independent Presidential candidate, if you're not in a position to make a difference by yourself, if all the power you have is your voice, then shut up; leave action to the rich and powerful, without criticism. That your voice has power is part of the point of democracy, and it's not hard to see why a man like Perot might prefer to make that sound less legitimate.

That doesn't sound like an activist. That sounds like "sucker doing other people's work for free", which doesn't sound like an effective plan for bringing about positive change -- those people tend to "weed themselves out" over the long run.

I'm not saying you shouldn't do things to make the world a better place, like: not litter, drive courteously, etc. (Although you should be careful about which things actually accomplish a net good.) "Be the change you want in the world" (attr. Ghandi) is a good motto to keep. I'm just saying that you shouldn't expect major problems to get solved by Someone Else at no cost to you, nor complain about someone pointing out the dirty river instead of immediately cleaning it up.