This is really sad (I remember trying to play EVE from Baghdad, but the latency made combat really painful, so instead I just read kindle books...).
I wish DoS had more "continuous" force protection levels; they seem to go from ~nothing (relying on host nation) to absurd overkill, with nothing in between, unlike DoD and others who have multiple levels.
What happened was they never had staffing appropriate to the mission, so they switched to using contractors for PSD (far more than DoD ever did; for DoD, contractors were support and logistics and low-level on base security).
The triple worldwide security contract (Blackwater, DynCorp, Triple Canopy) seemed ok, but then there were political/PR issues with Blackwater.
They try too hard in places which are permissive, and have no real idea how to operate in non-permissive environments (Libya!). Semi-permissive they also don't do well (if you built a 30 year building, Yemen was semi-permissive back in the day, but is now someplace I'd define as non-permissive for US forces).
If London ever gets to the point of needing a moat to defend the US embassy, we're pretty screwed overall.
Part of this is hiding CIA crap in the embassy, but a lot of it is just ego and committee rule (no one gets fired for adding security features...)