Interesting point and one I hadn't considered. How is "intent" determined? As a layman I think murder is murder whether the victim is a cop or a homosexual.
But after a little reflection, it seems to me it's entirely justifiable to demand stiffer penalties for cop killers. Police are representatives of all citizens and are empowered by the law, which represents us all. Anyone who flouts the law itself is flouting society as a whole. My point is that "hate crimes" legislation is bad law. Do you approve of it?
In practice, used as pandering for votes, no.
In theory, I don't know. Intent is intent, and if we are going to hold different penalties based on intent it is perfectly reasonable for society, through our elected officials, to determine what criteria are to be used.