SKR's denial that his ruling on two-weapon fighting has anything to do with attacks of opportunity is pretty clear - the only way he could be more clear is if he said something like:
So long as you're physically able to act (not sleeping, stunned, etc), you can always make AoO's with armor spikes and unarmed strikes with the Improved Unarmed Strike feat regardless of what you're doing with your hands, no take-backsies!
Let's say I was visiting a friend and asked if I could have one of his Belgian beers. If he responded, "I'm saving that for a party tomorrow but have no plans for the rest of my booze," the fact that he went to the trouble adding the exclusionary clause would imply that the said remainder is fair game. There's no need to go into specifics about how I could have exactly X bottles of this brand and Y bottles of that brand instead, or that the exclusionary clause did not include permissions to burn down his house; these things should be understood by the context of the statement.
Were he writing a rulebook, perhaps he should've added an explicit exclusionary clause - but this was a response to a series of questions on a message board, and the primary topic had nothing to do with attacks of opportunity or even reach weapons, but rather getting extra off-hand attacks while using a two-hander. As such, the answer he gave ("Not being able to two weapon fight with a two-handed weapon and armor spikes doesn't in any way restrict your ability to make attacks of opportunity with them.") was sufficient. I don't really see how that muddies the waters, but to each their own.
[editted for clarity]