Mostly they want to feel good, rather than be good.
Isn't that why anyone does good?
Surprisingly, no. Only a being following purely their emotions falls into that category.
Even a perfectly rational but unfeeling and immoral sapient will do good, because it is in their "enlightened self-interest". (Although it is called "enlightened", you can just replace it with "long-term", really.) Look into
game theory for scientific research describing this.
Many animals, humans included, have a strong sense of
fairness. In hominids and apes, it is especially strong (I've already shared the video about the macaque getting angry for their friend getting grapes and themselves getting cucumbers, although completely alone, cucumbers are an enjoyed snack). Humans helping other humans is a
natural instinct. (And other animals, too. And other animals have this instinct too, apparently because it helps the
species survive.) This is the "instinct" part, and is surprisingly opposite to "emotions", in a society where every action is judged by an insane ideological criteria.
People who are emotive, "emotionally-driven", are easily swayed by the emotion-based SJW ideology, even when it is in direct conflict with their instinct. (This causes a sort of a cognitive dissonance, which acts as a barrier against even considering the non-emotive arguments.) In very real terms, it is a human sentience worm.