The punk rocker may just not like Phish’s style. That’s cool- to each his own. Or he could be jealous that Trey Anastasio can actually play his instrument as opposed to just strumming three chords. It is usually the later. An interview with the Ramones revealed as much. They said they couldn’t play more complex rock and had to write punk music that they could play.
In fairness, the Ramones could make three chords sing. Not every band can.