The reason altruism was invented in the first place (by evolution) is that it makes a better society, and a better society benefits all of its members: of course altruism is always a good investment.duszek - - Helping someone is always a good investment, it seems.
If a person cannot help you in return then perhaps at least he will not be a wretch who freaks out and starts shooting at people. Which is also some kind of a reward, far-fetched perhaps, but still a reward.
Now, how do we convince the American right?