I think the offended woman has missed the point...
Being told that this used to happen, that slavery was a real thing and that many, many black people were treated as less than human, is all well and good. It should happen. It should be taught that it was and is wrong. Fine.
The issue here is that kids are being actively told to clap the guy in irons. They are partaking in the action of it rather than being a passive spectator. Is it different? I think so. Is it any more wrong than giving them cap guns? Does that prime them to go out and handle weapons, purchase guns, use guns, treat guns as toys? I don't know.
I'm kind of divided on this.