Regardless of whether or not it was a specific request (it would be strange if it was) it was still something which happened and Bethesda is ultimately responsible for it because they hired these morons to recruit voice talent for them. This is a step below Beth claiming that they are not responsible for quality of voice acting in the game (the piece missing is Beth checking off on it). It's all pretty stupid but note that Pete merely denies being responsible for the attempt to get Bill Clinton, not that they wouldn't have (or didn't have the desire to) used him if he had said yes. That question is one we'll never know the answer to.
All in all, this is pretty Beth-like PR, choosing something small, ridiculous, and pointless to correct and address rather than tackling the larger problems. When it comes down to it, no one really cares who they went after for voice acting, they care about the final product and the final product was pretty bad, or at least not good.