DT, there's no indication that Hamilton was a consigliere. on the other hand, there is evidence that he was a corporate attorney. Also, Altobello was a long time family ally. So, why would Michael view him as otherwise. Being clueless about the helicopter attack was not monopolized by Michael; none of the dons saw it coming.

Of course, as so many of us have posted in other threads, Michael could have retired from the life whenever he wanted. He let himself be pulled back in.