Actually it makes sense, since it’s all relative. I do want to “conserve” what was America, the greatness of its principles. And it was working a good deal for a good while. So “conservative” in that sense is not bad at all.
As for progressive, they do not mean as opposed to regressive, though that is a nice deception they want you to think. It’s a double entendre wherein the key meaning is “gradual”. They want gradual change so you won’t mind too much or notice.
Yes, we want to “conserve” our founding documents.
And your point about gradual progressiveness (is that a word?) is good. They want the Gullibles in that pot, slowly warming to a boil.