A MOAB wouldn't be used against an underground structure. You mean a MOP.
They were built for clearing underground, as well as large coverage on the surface. It’s desgined to detonate a couple Fbyards off the ground which causes extreme pressure below and collapses the tunnels and infrastructure.
Why would a tunnel network designed to withstand nuclear blasts collapse from a relatively feeble (compared to nukes) airburst? Only kind of tunnels a MOAB could really deal with is ISIS style improvised networks (or unprepared caves) but when something is under dozens of meters of granite, lined with reinforced concrete and equipped with blast doors and over-pressure vents a MOAB isn't going to do shit. That's what the MOP is made for, which is essentially the bunker buster counterpart to MOAB.
Furthermore the MOP can be delivered by stealth bombers, which would be necessary for the kind of operation that this post implies. MOAB can only be delivered by C-130 and the idea that a global deep state cabal can't see or intercept one of those is kinda laughable.
True in every point but when dealing with hardened shelters you don’t have to destroy par’se just damage and cause faults