It's probably better if they don't mention Thomas Jefferson, since they've decided he's a villain. They would insist he was an evil rapist of that slave girl - which is not proven, it was someone in the Jefferson family, either the man himself, his brother, or his nephew who lived with him, and contemporary accounts of his personality suggest it's very unlike Thomas to do so. But that is presented as fact, while never mentioning that he tried to include language in the Declaration about the evil of slavery, and that he was a proponent of abolition (gradual, carefully planned to avoid massacres like Haiti). Owning and keeping slaves was hypocritical of him, certainly you can say that, but you should be fair and point out that he also disliked the institution and wanted it to change, and that he was in serious debt so unable to free his own slaves.

As with any other history topic, they should be fair and point out both sides in context of the time period instead of just insisting "white man bad" all the time. Columbus has suffered a similar fate in terms of reputation, by dint of extracting sentences from his diaries out of context and refusing to tell the whole story.