And, in the 1800's, we didn't have an income tax. So, regardless, the immigrants were never drawing cash from the citizenry In any way that wasn't voluntary.
As for the shackles...I curse the British for allowing the slave trade. This country could've had a 1000 year reign without slavery. As it is, I think things are winding down, and part of it has to do with us still trying to solve the problems that slavery visited on the people's of this continent.