Brigianna, I don't see what's the difference between what you call "personal comfort" and social expectations? Do you use a drape when nursing in private, for your personal comfort? Or only in public? Because in the latter case, I'd find it very hard to not see it as guided by social expectations, and in that case I wonder why you don't seem to be interested in discovering the implications of your adherence to social expectations for other women, for women in general...
If your "personal choice" is causally related to how other people would view your body (and unless you use a drape when no other people are around, it cannot be denied such a relationship exists) it would seem logical that you do not distinguish between a nursing relation and other people's rights to interfere with it (by criticizing, observing or opinionating), so sure it is related to the basic principles of lactivism! (namely the right of the nurser and nursling to conduct the business of their nursing relation without interference or obstacles from the outside)
From the pictures I've seen, I also believe the fashion police should make drapes illegal, but that's a diff story
The difference, to me, is that I'm not doing it for the benefit of other people (to avoid offending them, to impress them, to conform to social expectations)--I don't go for that stuff. I do it because I, personally, want to keep myself covered. Because my body is my own, and no one has the right to look at it. Not because of "what they would think" or "they might be offended" or "it's shameful," but because I want to protect my own privacy. Social expectations don't really have anything to do with it at all.