Is there more than one interpatation to laws?:
They are treated differently because attemepted murder and an officer involved shooting are completely different things. 

If a citizen, as you put it, "commits attempted murder", he goes to jail when the investigation has been completed and probable cause has been found. Also, he does get bail for an attempted murder charge. People also get bail in murder charges, so I'm not really sure where you are going with that.

If an officer gets in a shooting on-duty, he/she was probably faced with a direct threat to his/her life or a victim's life. Even if justified, the shooting will be investigated to make sure all laws and policies were followed.

It seems you want to convict the police before all of the facts are investigated. Remember, innocent unitl proven guilty.