my work had the same issues, anything like "gun, firearm, ammunition, hunting" or the like would set of bells and whistles. WARNING DANGER WILL ROBINSON.
It used to peeve me, as we were allowed small amounts of casual use, such as reading CNN and such. But whoever programmed the filters had it set that anything even remotely related to guns was blocked
Hence my acquistion of a laptop with a wireless card. Now I can buy ammo or post on this forum from anywhere