What they dont know, is that slaves had a value. The irish were worthless. The conditions on the ships that brought immigrants during the famine were way worse than slave ships. Some of those ships had 1/3rd of the people on board die in transit.
When they got here they were hated and were only able to find the lowest paying labor jobs. They built the railroads, worked the mines, built houses, and so on for far less pay than "whites"
I could go on all night about how fucked up my ancestors were treated, but ill spare you the reading
Black slaves were treated horribly, but they were a commodity and worth money. Yes, some slaves were beaten and abused but more often than not they were taken care of. Healthy slaves were capable of more work.
The ones that tried to run away were usually killed or tortured, but again, if a slave worked hard he or she would have more often than not been taken care of.
Slavery is wrong.... But its over now, until some guy tries to trade you for a fat cow, lets just remember it as a fucked up part of American history.