There's a difference between having a view and spreading apologia for public consumption.

For example, surely anti-abolitionists' apologia made them more complicit in the continued institution of slavery than those who chose not to make excuses for it did, even if they themselves did not own or facilitate the sale of people.

We don't seem to have a problem with assigning some responsibility for abolition with abolitionists' own apologia, some of it still read in schools today.