There are many crimes that are crimes only against cops giving them special status by both allowing them to be a specific victim, and by essentially making them immune from such a crime since they can only be a victim to that crime. The same with assault on a police officer; killing a police officer, etc. Cops already have plenty of special statuses and are very well protected anyways.
http://www.startribune.com/minnesota-police-officers-convicted-of-serious-crimes-still-on-the-job/437687453/
On top of that, we have in one state dozens of officers that were convicted of serious crimes still on the job.