i assume there's no evidence that the women came from specifically bad countries, other than the fact they are black
But there is. all you have to do is some quick research and you can find the origin of someone's ancestry
or, is it fair to tell any african american who was born here to go back to their shit hole ancesteral country if you disagree with them?
You have to understand the context. He not just saying "I disagree with you, go back to where you came from", he's asking "if the system is so great why don't you go back to your country origin and test it out there and then come back and show us how it's done?", which really boils down to, "I don't want the USA to become the next lab rat for the socialist experiment, take it to a country that has nothing to lose, and then come back once you're done".
The fact that he invites them back afterwords is key in recognizing that the statement isn't racist.
But why choose their country of origin and not some other country?
Because by using their country of origin he is reminding them of their own history, hoping that some common sense would spark in them and that they would recognize that by being socialists, they spit on all of the dreams of freedom that their parents/grandparents had.
It's called emotional appeal and using it in this manner is not racist.