Thunderbolt requires physical access to the machine. Wireless can leak and potentially be available outside of the building. That it is the biggest concern with Wifi.

Is there a likely hood of WPA2 AES being cracked? Yes, it is very small but it is still possible. Also if a secure device is captured by an attacker and they steal the credentials to access the wireless network they can now come and go as they please. At least with physical they would have to enter the building and plug in.

Are other attacks feasible, absolutely and I will grant that, but having wifi enabled just doesn't work for certain situations and where paranoia runs high due to the work that is being done.