Any civilian would get a trial and due process. These cops got suspensions and terminations without trials. If that was John Q. Citizen working at the mall who got fired for domestic abuse you'd be screaming bloody murder about due process.
Oh, if that were only the case. Timothy Emerson was thrown in jail for possession of a handgun after his wife requested a restraining order for some trumped-up B.S. Emerson never got a trial to see if the restraining order was warranted. There is never a trial to see if domestic violence restraining order is warranted; they are issued as a matter of course in many divorce cases. Your assertion is absolutely, 100% wrong. Any civilian who did these things would be forever denied the right to own weapons; federal law says so.
For the record, here's what really happened to these cops: "None of the officers was prosecuted. Four were fired, one resigned, 19 were suspended for periods of time, seven received warnings and 48 were cleared of the allegations leveled against them." Sounds like they all got 'due process' to me, and they got off lightly.