That is a new explanation of white label I've never heard before.
My experience is white label vinyl records could be bought in very niche record shops, they were music not released on an official label yet and the samples often weren't cleared for release. I owned a few back in the day. This is how DJs had tracks months before official release.
This explanation is the one I’d heard before and it makes a lot more sense to me. My memories of the 90s is that underground DJs were happy to share their music¹ with others and wouldn’t have sullied their vinyl collection by ripping off the labels. Maybe some DJs were territorial but most would be proud to show off the fruits of their record hunting.
¹ So much so, that they were far less willing to share the decks.
