This is the same sort of thing as the good old metal zipper of decades gone by, but with softer teeth.
Get caught in one of these and it's only a matter of being accidentally gummed, and not being actually deliberately dismembered by something desperately nippy, as happens with metal zippers, which don't play well with others, and which aren't amenable to any sort of negotiation.
A molded plastic zipper is in fact a miracle, composed of polyacetal resin, when it's not composed of polyethylene, both ever-so-popular plastics in use all over. The polyacetal stuff may be called Delrin, which is a brand name belonging to DuPont (E. I. du Pont de Nemours and Company). Remember them?
Either way, whether you've got polyacetal or polyethylene, the teeth of such a device have their color built right in, and not painted on as is the case with metal zippers, when they are not either a naturally silvery color (probably aluminum) or a naturally coppery shade (brass).
As if you cared, out there in the bush, when all you want is something to eat, a bath, and a place to lie down for a month or so in front of a TV set.
But on the other hand, if you didn't want to get out there and hike around like crazy, and stink, and attract vermin, and get your hang-doodle caught a zipper twice a day (because you're crosseyed with fatigue), then why did you go?
Be glad then. You're lucky.
Be glad that you are hiking, and not back behind that desk in that cubicle, or stocking shelves at WhiffleMart, or in that workshop or whatever, dealing with morons, and slowly becoming one yourself. Be glad then that you can hike, and have zippers to play with. Zippers on your pants, your jacket, your sleeping bag and on lots of other stuff, and that you don't need to pin your clothes together with thorns like all the other animals do, though they are actually quite clever in their own ways, but hardly ever get to eat glop from a titanium pot and never have the slightest chance watch TV, even on their days off.