Surely the world will be a better place, at least marginally, if people have a better understanding of Kant and Hegel, if Marx's thought its studied and appreciated, if people gain a better understanding of Fichte, whose philosophy is far more important than people realize.
The problem is that many who reject Marx do not read him, or read him only by bringing prejudices to their reading that prevent them from understanding him.
Kant does not think there is anything wrong with being beneficent from sympathy. He thinks we have a duty to cultivate sympathetic feelings by participating in the situations of others and acquiring an understanding of them. He thinks we also have a duty to make ourselves into the kind of person for whom the recognition that something is our duty would be a sufficient incentive to do it (if no other incentives were available to us). That's what he means by "the duty to act from the motive of duty".
