You're in the military. Regardless of service, you're job is to keep the good guys safe by bringing death and destruction to the bad guys. To do that, you will have many tools: airplanes, deck guns, torpedoes, small arms, etc. When you don't get the training in one of these tools, it ceases to be an asset to you when it may be necessary.
Everyone in the military needs to know how to shoot. Period.
Everyone in the military needs to know how to shoot. Period.