Am I a bad person for laughing at this? Probably.
On a more serious note: this is the worst nightmare for anyone who has to manage a mobile/remote workforce (or in this case, a large remote customer-base). The idea that some code could break the ability to for a system that depends on communication to communicate is why there is such a thing as a development environment in many corporations where MS updates, AV updates, etc. are tested NOT on the production network. Of course, many corporations have had to cut back, and due to budgetary restrictions many companyies have effectively outsourced their testing to the vendors releasing the updates, depending on the vendor to test and not release some ridiculous update that (for instance) pushes out a firewall rule that stops the system from communicating, or as in this case, an update that nukes the AV software itself, and the ability for the AV software to repair itself by auto-updating. I do NOT envy any IT managers who are at a corporation using Sophos who let their users auto-update and don't do as I previously mentioned (i.e. test the updates/definitions). Ouch.
And now back to laughing.