consider this: there is a factory. it employs 100 workers, generates some amount of value which is split between worker salaries and profits for the owner. now someone invents a robot which can replace 90 of those workers, and cost the less to run and maintain than those workers' salaries. should the factory owner make the switch? of course he should, it's insane to make humans work when a machine can do their jobs. but now what about the people who were working there? they could be forced to retrain and find new jobs (not always possible). they could be kicked out to fend for themselves (what happens now). or the government could tax the means of production highly enough that it could pay them in welfare what they were making in salaries. the factory owner would be no worse off, the workers would be better off, and the government would have corrected for the fact that wealth tends to pool in the hands of the people who already have it, because they are the only ones who can afford to acquire the means of passively generating income.
in terms of morality it seems better than making person A "forcibly"[0] labour for person B simply because person B happened to start out with a lot more money.
[0] no one is putting a gun to his head, but if it's either work or starve you cannot call it uncoerced.