Taking your analogy at face value, you're saying Fred shouldn't comment on ISIS, because logically that's not his area of expertise. Which, I'll grant you, is fair and makes sense.
Unfortunately (for your analogy), he happens to know A LOT more than you or I about Marrone leaving, rendering his opinion completely valuable, especially when applying your own analogy (as it happens to actually be his area of expertise).
You do realize the fallacy in this specific anolgy as it pertains to your argument, right?
Also -- does it really matter? I mean at this point what it comes down to is you have a bit of respect for Marrone still, and most of us do not. Taking shots at Fred or Aaron Williams is arbitrary and pointless as it does not deter nor strengthen from your consistent protest.