Ditto all of the above. Some slave owners were eager to protect their "investment" and treated their charges well. Since I don't know the site, I can't comment; if you want, you might ask for documentation. Sometimes there are letters and journals to support what the guides say.

There are many accounts of slaves who stayed on after emancipation. If they had been treated well, it was probably a wise choice, and certainly preferable to venturing to an unknown place, where you didn't know how you might be treated. Let us not confuse abolition with equal rights - even abolitionists did not believe that blacks were equal and should be treated as such.

Uncle Albert, who once belonged to Andrew Jackson, long outlived his former master, and chose to stay at the Hermitage. He is buried in the garden there. Also, at the Belle Meade Plantation, there was a groom (who had been a slave), who stayed there, because he loved horses, and was damn good at his job. He was so good at picking horses, they just gave him the money and said, here, go to market and pick out whatever you want. He was The Head Groom and had a position of respect and authority.

So... in answer to your question.... perhaps ask them what they have to support their statements. They should be willing to tell you.