Why can a cop break the law without being in the act of enforcing the law?

All of these areas to which you are referring to are only off limits for those NOT authorized to be there (ever seen those signs in the median crossovers of freeways that says Authorized Vehicles Only). Police, Fire, Ambulance and other public safety vehicles are authorized to be in those areas, you and I and other regular citizens are not. So your thinking that they are breaking the law is completely incorrect. You just sound like your sour because you've been busted for speeding (which is breaking the law).

Also, police cannot use laser radar systems while moving.

-my point is....what gives them the power to break the law just to catch somebody else breaking the law. They can radar cars, check stickers, etc..while driving or in the normal course of a traffic stop, or by being parked legally. I mean, if they can't meet their revenue quota legally...then tough cookies......And maybe it is legal, but if legal, then there has to be some sort of legislation providing them that power...so far nobody can produce this legislation...

They are not breaking the law by sitting in the median. The law specifically allows emergency vehicles to use the median

Using radar to catch speeders?

Checking for inspection stickers and current registration?

Where would you prefer they were,

getting doughnuts?

Stereotyping!