No, but law enforcement resources are finite, not unlimited. We could spend 100% of the city police budget on catching speeders alone. Or we could spend 100% on busting marijuana users. Priority decisions have to be made.
My comment deals with your view of the law not the finite resources of law enforcement. As to the resources of law enforcement, you could make the same argument in favor of not enforcing any law you don't personally like. IMHO you are promoting disrespect and basically supporting criminal violation of the laws as established by the citizens of the US. This is anarchy.