Personally, I find it obvious not to be able to attend a restricted raid while having been buffed like that. You didn't even mention an on going event, just that an ET buffed you. Im taking that information as you just abusing being given a buff. Opera's frustration is justified imo.
While I was still around, there was a CI operative that was scaled HP buffed and we had told him that he was not able to attesd a raid because of this until he was reset. He later attended a raid and got in a lot of trouble.
Unless the event involved all of MTF and CI was on board, then I would say this should have been permitted. I don't believe this was the case, since only you seem to have gotten in trouble. Next time you're buffed, you probably confirm it's okay
-support