I'm trying to avoid getting into a discussion about exact definitions of democracy, but what I see here is that you're arguing that the bigger a government is the more democratic it is and thus it is justified in imposing its will on other democratically elected governments by virtue of its size and I don't think that those things follow one another.

If you want to say that of course a higher (which is typically defined by size, but I guess also potentially authority or ability to enforce rules or some other concern) level government overriding a lower level government could be anti-democratic then we're just arbitrarily picking and choosing what we believe is democratic or anti-democratic which ties back to effectively expressing moral statements of good and bad.

Leaving aside natural rights, and the complexities of state sovereignty in the United States specifically.