but I don't think that America really subverts them for the purpose of oppression. The US is perfectly capable of oppressing without appealing to those ideas (indian wars; japanese internment). I actually think the US means it (and thinks that it can) deliver democracy without being oppressive.

Hanlon's razor. But the difference here is, in this case it is impossible to not be incompetent. Just as it is impossible to deliver what you intend for the world without being incompetent in the sense of being 'non-oppressive'.