What do you think about Periphery often being labeled as Metalcore?

As you might know, the folks at r/metalcore often bring up Periphery as being a metalcore band, but I can't say I agree. I would say they are quite clearly prog metal, but I suppose they are on the heavier side of prog and definitely have more appeal to metalcore fans than other prog bands (even though I actually love both). I know genre is obviously irrelevant when everyone is enjoying the music, but just wanted to know some other people's thoughts on this!