Well he said 'the metal mainstream and super-edited productions' which is something else than 'mainstream'. Their more recent albums, especially the guitar-driven songs, do sound like they try to cater to the 'metal' audience. And you can't really argue that Haken does have 'super-edited productions'.
That said, it's still pretty much a needless comment, and coming from a musician it almost reeks of jealousy. Haken are definitely more popular than they were a few years ago and, judging by their sizes on social media, they're also bigger than The Flower Kings are, so in that sense, yeah, Haken are 'more' mainstream, I guess.