Majority of people use drugs to escape problems and not get high why shouldn't he be hired as a police officer?

Drugs affect your judgment, law enforcement officers need to be alert, sharp & attentive. Their jobs demand a level of professionalism & being able to use good judgment. When you are altered on drugs, alcohol or stress, you can not do your job properly.

Uh, how about because it is a bad idea to have a person who will not obey the laws, then trying to enforce them and locking up other people for not obeying the laws?

And stop with the excuses for such behavior.

Because someone who has to turn to criminal activity to escape their problems is exactly the opposite of a police officer.

I disagree with your premise

cause he might be driving while high, thats why, and they dont want a police officer high while on the job

So that's how you've rationalize your drug use? No, the majority of people do NOT use drugs. And drug users are not very good candidates for the police. They can be blackmailed, for one thing.