The worst damage is that you convince them to stop trying; if their efforts are doomed anyway, why not just breed for a life of leisure instead of getting a skill and earning a living? That is what the last 50 years have given us - and them.
As soon as the slave are freed, the Democrats begin to tell them that, though they may be free, they'll never make it because they will always be victims (i.e. losers).
Satan couldn't say better himself.