No you are making a mistake. The AR-15 can be converted to a .22LR. The .223 is a .22 caliber. I never said it was a .22LR (example of a Ruger 10/22). No matter how you define it, the AR-15 is a .22 caliber. .223=.22, but not a .22LR. Yes there is a conversion kit to go to a .22LR.
No it is not a .22 caliber. A .22 caliber is a .22 cartridge and a .223 is a .223 cartridge. If you think they are the same try shooting a .22 round out of a NON CONVERTERED AR-15. Besides bullet diameter was not the meaning of your post. You made the AR 15 out to be equivelent to a 15 year olds .22. rifle and it is not even close. I happen to be a firearms instructor (pistol and the M-4) and the comparison of a .22 caliber rifle and a AR-15 is laughable. The ballistics of the two rounds could not be more different. It has nothing to do with the right to bear arms or things like that, that is another discussion I think and not my point. An AR-15 is a .223 weapon which is substantially different than little Johnnies varmint rifle.
PS on the edit. It doesn't matter what you personally believe about someone having a firearm. If they abide within the laws then so be it. There is much more behind the Tank story we do not know. If he broke the law than bust him. I do find it humorous how a person breaks a minor gun law and they are condemned to hell forever, but if they break a drug law it's just no big deal.