I personally think hate crimes are fucking stupid, but liberals love them.
If someone is targeted for violence specifically because they are police, it should be a hate crime.
How could liberals possibly be against this?
It doesn't fit the category of a hate crime. After all, what is a hate crime? A hate crime is a crime committed against a very likely Democrat voter such as minorities, gays, cross dressers and so on. It's a crime that violates our Constitutional right of Equal Protection under the Law as it assesses harsher penalties for the same crime others commit not categorized as hate.
However you are correct that our laws do not protect police officers nearly enough. Assaulting a police officer should be a felony that carries a minimum of five years in prison on top of other penalties for additional crimes committed.