That makes us imperialists today?

No. But that wasn't what you said:

But nothing America's ever done has been an effort to build an empire, take over someone else's land, or anything of the sort.

I think that the article you quote may be a little apologetic. I may be a little harsh. The truth is probably somewhere in between. Regardless, it was to the US's interests to have that rebellion succeed, and they did what needed to be done to get it, regardless of the exact methods.