I've never thought his silence made him look weak. As I've said elsewhere on this site, I wouldn't want an administration that was entirely transparent, especially during this sensitive period that is the hiring process. Now that the major hire has been conducted, it makes more sense to ask for rationales, as there's less risk of revealing important information to other teams.
I don't think Mike McCarthy, Ted Thompson, Mike Sherman, or anyone else owes us explanations for everything they do as soon as they do it. Sports is like war -- information has to be held close to the vest.
Also, I'd lose a lot of respect for these guys if they were airing laundry out for the world to see. For all we know, some of these firings were for personal reasons (chemistry, different vision, etc.) than for performance on the field. Let the guy go with your thanks for all his hard work, and give him a chance to put food on the table somewhere else.