I don't doubt your good experiemce with propane. The problem is your experience is that of one guy.
I'm sure there's someone out there lubricating his 5.56mm M4 Carbine or AR15 with KY-Jelly with no problems. But don't expect a big DOD contract for this stuff to replace military CLP.
Use our-of-spec products at your own risk. When in doubt RTFM, those factory boys actually test this stuff and occasionally know what they're doing.
The price of green gas is, of course, obscene. I have no insider knowledge but am convinced the cans are all filled at one or two places and they put whatever label the customer wants -- this is called private labelling. You can bet KWA is buying green gas as well as buying their branded BBs.