Both views have merit, and you should read the comments for additional insights. There were some excellent comments posted.
As for me, I'm not a fan of parenthetical explanations. I'm probably just over-reacting to the heavy use I see in student and practitioner writing. But I say if you have an authority that makes a point for you, state the point then cite the authority.
But I, too, am annoyed by the citing of an authority without any explanation of why it's being cited. So if you want to cite an authority but say nothing about it, think hard. Real hard.
Ultimately, in rare circumstances, I can accept parenthetical explanations. In all fairness, I guess I should say I'm not a fan of the heavy use of parentheticals.