It can be argued that altruism itself generates dividends for the whole of society, and thus acts of altruism can be seen as self-benefiting, adding a middle that isn't otherwise considered.
A good example might be: "I pay taxes to help welfare recipients because I'm forced to." vs. "I pay taxes to help welfare recipients because it's the right thing to do." There is yet another option of "I pay taxes to help welfare recipients because it has economic benefits and because I don't want to personally deal with the homeless everywhere I go." The last one might sound heartless, but I think that it might appeal to more conservative members of society, and it also turns out to be true.