Some people claim progressive rock is bombastic, or pompous. That is, it's full of showy self-importance. If so, the claim is emotional, based on preference. But this is beside the point. Induction into the Rock And Roll Hall Of Fame should be based on influence and contributions.
Some people claim progressive rock is pretentious.
Either the artists are using the showy self-importance to cover up a lack of skill or that the artists have overreached and don't have the skill to match the attempt. Sometimes this is true. But for the most part, the progressive rockers are regarded as virtuoso musicians, and pretense comes out when these virtuosos attempt to reach farther than even they can reach. I could go on, but again, this misses the point. Along this line is the question of motives.