I think they're thinking that people like them are in the majority and they're trying to incite the most desperate or violent racists to start attacking minorities under the cloak of darkness. I've worked and spoken with crazy right wing assholes my whole life. They're the type of people who would easily murder or rape if they think no one is watching and they can get away with it.
The funny thing is religion used to reign a lot of them in. The true believers actually felt like God watched their every move, but most church goers don't even really act like they believe the shit they spew anymore.
I'm just speaking from experience growing up in churches. The people who would go to church and only behave because they think God is watching are the people trying to get their reward from it. I've known some really decent people, but they were very rare. The majority were there for themselves.
The thing is I've seen many of those same people keep the rhetoric, but leave the churches for the most part.