I wasn't part of the conversation obviously, so I might be completely missing the point or the tone of their comments, but maybe what they meant was that freed slaves didn't exactly have a world of opportunity open up at their feet once they made it to the North.

They were free in name (if the slave catchers didn't haul them back), but let's put it this way; nobody alive today, black or white, would consider the life they had freedom.

Harriet Tubman was a hero. And escaping to the North was obviously better than being enslaved in the South. But it's a matter of degrees. I think keeping those degrees in mind is an important part of continuing to make progress.