I guess I read the article differently from many people. I didn't get the impression they were raising a gender-neutral child, just that they were going to follow their child's lead about what his or her gender would be. Once Storm felt ready to declare a gender, and/or let people know his or her sex, then Storm would do so. Until then, they were keeping knowledge of Storm's physical sex restricted to close family members. To me that's a far cry from acting as if Storm doesn't have a gender.
Also, only telling close friends and family Storm's physical sex 'for the time being' isn't the same as keeping it a secret. Storm will know, people who change his or her diaper will know. At four months old, to whom else does Storm's physical sex matter??? They said they'll keep information about Storm's sex within the family as long as everyone's comfortable with it, so it sounds like they're well aware that they won't be keeping this up forever, or even very long, and have no intention of making their older children shoulder a burden they don't want.
I think there are a lot of fears being read into what this family is doing: fears that Storm won't be allowed to express any natural femininity or masculinity he or she might feel. I do think some people have swung to that extreme in reaction to polarized gender roles. But I don't think that's what Storm's parents are doing- they seem to be all about child-led self-expression. I can't find fault with that.