I think part of the reason that Liam is getting flack is because, while his subsequent posts were reasonable, his initial response was not. Hop turns are not the best choice for skiing steeps or crud--though occasionally you do need to retract aggressively enough to pop your skis free so you can change edges when the mank is extra gooey. Moreover, the OP was asking about steep refrozen crud--and icy conditions are the last place where a hop turn would be helpful. When it gets slick, you need progressive edge engagement throughout the entire turn, not the late slamming of edges that results from a full hop turn.
PMTS is not religion--you won't go to hell for hopping a turn or three. But what practitioners of PMTS learn is that when you are able to carve the high C portion of the turn, you get a level of precision and control that is incomprehensible to those who don't ski that way. Much of the PMTS versus the world type arguments stem from this lack of understanding. Developing the skills to carve the high C takes time, effort, and persistence (not to mention a basis in understanding how technical actually skiing works). If you don't ski that way, the arguments for doing so aren't going to make much sense. If you do ski that way, you won't consider anything else because anything less than high C engagement feels sketchy. Hence the howls of protest from the PMTS folks whenever anyone suggests something that involves twisting the feet as a general solution for anything.
Yes, full hop turns may sometimes be necessary, but nobody who skis the high C would ever treat them as anything other than an emergency maneuver, or an option of last resort. The fact is, when you can carve high C turns, having to abandon the high C is scary. You understand exactly what you are giving up and when you have to resort to something like a hop turn and you hate doing it because it is so much less controlled. In the case of hop turns, you also hate doing them because they require so much physical effort and they just don't feel good. Fighting gravity sucks--especially when you are used to treating it as your plaything. Hop turns are not, in the PMTS view, good skiing and even if you have to use them once in a while, that doesn't make them worth talking about. You get better by practicing the ideal, not the one-offs.
I don't practice hop turns because I find that if I need to do one, I can. They are just an extreme application of movements I already have. Interestingly, after becoming a PMTS skier, I found that my execution of hop turns actually changed to match my new movements. All of which tends to support the argument that if you have the skills to be where hop turns might actually be warranted, you will instinctively know how to do them should you need to. Really, I don't consider hop turns to even be a turn, and as such, the only time I consider using them is when I'm somewhere that is so steep and narrow that there is simply not enough room for the skis to work.
That said, the crux of the argument really boils down to what kind of skier you want to be. The DesLauriers teach skiers to ski the whole mountain while PMTS teaches expert skiing. There is a difference. Most all mountain skiers are not experts. If you want to be an expert skier, perfect your ability to release, transfer, and engage until you can do it in any conditions and on (almost) any terrain. Practice the ideal and strive for it at all times in your skiing.