There's been a general conservative response to liberals criticizing House Republicans for not reading the superseded text of the Constitution that is something to the effect of, “don't liberals understand that the three-fifths compromise diluted the power of the slave states by preventing them from counting slaves as people for the purpose of apportionment?”
This is true -- and also completely irrelevant to the argument that in reading the Constitution, we should be actively acknowledging that America used to be a slaveholding society and for that reason the Constitution was flawed at its inception. The fact that slaveholders would have preferred that slaves count as a full person doesn't litigate against reading the whole Constitution, including the parts that handled the matter of slavery in a country founded on the idea “that all men are created equal.”
I will say that remembering the debate over the three-fifths compromise is useful because while we tend to grade our predecessors on a moral curve regarding history and racism, the fact that the slaveholding states wanted to count their slaves as people for the purpose of apportionment is a reminder that they knew very well that that they were enslaving actual human beings and not chattel.
