I can see how the folks at PA, are probably shaking at the seams, revisiting all the arguments and discussions about so many bands, and so many details and so many this and that, enough to make you want to leave the room and have a smoke, or tea.
For me, both terms, really did not mean anything. I was already aware of many expansions and roads in theater, literature, and art, BEFORE, what we discuss as "prog" and "progressive", to the point that I actually found most of the music, simply regressive and not even that interesting ... but this has a tendency to make folks think I'm being condescending, and I am not. If you go through my collection ... the first thing you are going to see is the variety, and how an Einstein theory, in all likelihood, is simply misguided physics and ideas with manipulated mathematics! I would hate to think that music is something like that!
I've always looked at all arts as an "expansion" of our understanding, regardless of its form ... some of which I can relate to (Guernica is easy for me given my family!), and some which is ... too far beyond me (Miro) to many others likewise in music, and in theater. I don't like Ionesco, for example, and some think that he is the supreme "surrealist", when he is nowhere near surrealism, and probably the opening of the door to the American living room TV since the 1950's! It all became "visual" ... and music, is highly visual for me, and is my way of defining what is good or not, for my tastes.
Has nothing to do with its "rating" or its "definition". Good work always stands up ... regardless! And a place like PA really helps you find that and listen to it!
Enjoy it, and stop worrying about the color of the shorts!