Because they're the AF.Callsign appears to be Havoc. Can someone explain/defend why the AF dudes give themselves ‘cool’ callsigns? It’s so much more lame than the ones that celebrate epic screwups or personal shortcomings.
That said I think there's some variability between the USAF communities. @nittany03 and I had a VT IP who's callsign was some acronym along the lines of "BS you hit the pickle switch with your elbow." He was an A-10 guy. The AFSOC guys I've worked with seem to eschew them as "stupid things fighter guys do."