"Soft" suggests to some folks that they are not critical. It is not the skill or purpose of the skill that is "soft" but rather its definition. That is, they are often not well-defined or dimensionalized, and are broached on an I'll-know-it-when-I-see-it basis by those doing the selecting. Of course, if those doing the hiring are operating with an underspecified notion of what these revelant skills consist of, and what "more" and "less" of the skill might look like, chances are pretty good their intuition will fail them from time to time, and that they may confuse irrelevant or distracting characteristics of a candidate with real and valid evidence of specific soft skills.
If there is any disregard for soft skills out there, it likely stems not from any actual and demonstrable unimportance of such skills, but rather from disappointment in the outcomes that occur when people have not put enough systematic thought into what such skills need to consist of in THAT job, and what reliable behavioural evidence one would need to look for. It's a bit like declaring that one doesn't like Indian food, after eating some prepared by a person who didn't know very much about it.
The list you provided is a very good one. Not comprehensive (though I gather you knew that), but precise and related to specifics about the job, as opposed to bland underspecified categories like "leadership" or "communication skills".