Did you just realize this now? The name "Department of Defense" has always been a euphemism. The last time we were in a defensive war was World War II--ironically, when the DoD was still called the "Department of War."
It’s not “whataboutism” because it’s relating to the same event, not a different event. In context of the facts, it seems like your complaint is that the name is being changed to accurately reflect what the DOD was already doing.