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Alternatively: "Before you can post, please write a driver for [remaining piece of closed hardware, from e.g. an Android phone] and get it accepted to mainline." or "Before you can post, please persuade [company x] to release full documentation on [chipset y] without the requirement on an NDA. Bonus: Free 1 year subscription if you can get NVIDIA to release docs for all their hardware."

But seriously, I think the best way to handle this is via a 'report spam' button, as outlined in other comments.