You can't judge people for wanting to re-arm as there is nothing wrong with doing it. People like seeing how many kills they can land in one sortie, so what? Score is a big part of the game for a lot of people, just like a personal record in a race is more important to some more than others. I see no issue with giving someone the ability to change parts of the load-out (fuel and ord, not guns though) if they feel like it. I know I've re-armed before because I liked the quasi realism of taxing off, waiting to be re-armed, and then re-starting, taxiing, and taking-off all over again, it had nothing to do with the number of kills I had. Hell sometimes I'll even taxi from the hanger to take off and then taxi back to the hanger after landing. Whatever floats your boat.
I also agree that FSO's could definitely use this ability as well.