Hmm I dunno if it's a comment about their next musical direction or just a dislike of the term "pop punk", I guess since it's sometimes used in a disparaging way (although that's silly really since pop can just mean melodic and catchy which is exactly what Green Day's music is).
Given that it could easily just be a throwaway comment about disliking the term or perhaps what the term has come to represent (shitty boybands with guitars) it's going to be extremely tiresome if fans start bitching when they don't get the hardcore punk album they were "promised".