Frankly, this is just bizarre. It's utterly routine for parties to contracts, or similar legal arrangements, to identify new possible constructions of their entitlements and powers under those contracts and try and exercise them.
Sometimes this is to try and wriggle out of things. Sometimes this is to try and get others to do new things. Sometimes it is "offensive", sometimes "defensive".
Courts as well as parties develop and change their understandings also. I probably can't mention the best-known US examples for board rules reasons, but I'm sure you've heard of some of them.
WotC had a view about the limits of its legal powers when it posted the FAQ. It now has a different view. It seems fairly clear that Dancy
wanted a licence that would bind WotC in ways it now asserts it is not bound. Presumably his lawyers at the time thought they'd achieved that, and that WotC believed they had achieved that. Now WotC asserts differently. It may have been wrong then. It may be wrong now. There's no reason to suppose that it was lying, or self-deluded, or even confused (not all error is confusion), on either occasion.
I reiterate my view that talk of WotC lying, or being deceptive, adds little to the discussion. As far as the legal significance of the FAQ etc, here's the earliest post I know about that made on these forums. I posted it in mid-2008:
GSL & SRD -- Comments, Questions, and Hopes