Because he is just as dirty as they are. Cops do this shit all the time and other cops know it and do nothing to stop it.

That makes the ALL CORRUPT. The Chief is protecting his job by protecting the criminals who serve him.

He keeps harping on how they will do a complete investigation for the officers and will not make any conclusions. But if anyone of us do anything, they immediately put the cuffs on and throw us in cages. Then we have to fight to prove we are "not guilty".

A negative cannot be proven.

The cops are always assumed, presumed and treated as if they are innocent or justified before any charges are even considered.

That is not equal treatment under law and therefore, unlawful and a crime itself.