It is perfectly congruent to simultaneously support people’s right to do something and oppose their reasons for doing it.

For instance, I can support the right of the southern secession, but emphatically reject slavery, even though it was undeniably a factor in the decision to leave the union.

To assert, or even imply, that I am a racist, or that I must somehow support slavery simply because I believe a group of people have the right “to alter or to abolish [government], and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness,” represents a logical fallacy.