Agreed. My worry isn't whether dyneema is dyneema but rather is the "dyneema" I'm being sold from a real dyneema manufacturer. If it is, great. End of story. If it's not, I don't want some cheapo polypropylene rope rated for 300lbs going on my winch drum and me not finding out until I'm stuck in a mud hole 15 miles from uncle Joe's cabin....It's all the same, save for quality of splices, shipping time, color, fairy dust, etc.
This stuff has far more customers in the maritime world and there's a tiny number of manufacturers of the raw material. All these vendors are just buying giant spools and selling chunks. Up to you if you care about the value add, but it's all essentially the same.
Dyneema is so amazing IMO that it's just one of those things that should entirely take over the winch line market. The end