I don't really agree. I have a lot of extended family who are Republicans. Not a single one if them thinks of themselves as a bigot, much less racist. Some have black friends. They are mostly 'law and order' people and their first assumption is that a black guy did it (although most crime is committed by whites) and when they think about people on welfare, the face they see is black. Even the ones who have received some sort of assistance themselves.
They see themselves as 'real Americans,' and are completely unconscious of the fact that they came from immigrant stocks who came to America under circumstances not unlike those of the recent immigrants they deride.
There's another dimension to the L&O crowd. They want the foot of the police on the necks of minorities, and if that costs a few lives, so be it. Why? Because they believe without what many would call oppression but they would call vigilance, the criminal elements will grow and take over.
Here in NY, it's openly said that ending stop and frisk means that the city will descend into chaos. And that is the view of most of the police. I would guess that the attitude of the Ferguson police is the same if not more so.
So, do conservatives want more dead black men? Not in a body count sense, but they are willing to accept more killings if that keeps the lid on crime.