There's plenty of examples of legal oxymorons. For example, the idea that one can be too drunk to consent to sex but apparently able to consent to driving and thus get a DUI.

I'm not against 18-20 year olds w/ CCW. I'm against the ineffectiveness of this bill. One would think that maturity at the automagical age of 21 is the onus for being able to drink, yet I have a feeling that the same sponsor of this bill would blanch if it was suggested to lower the drinking age.

Don't look for consistency in the "law". You won't find any.