I see two reasons for that. First, the GOP candidates are all further from the political mainstream than the Democratic candidates. I'm not criticizing any of them or their politics, but they're very unlikely to get elected -- Scott Brown was the Republican with a chance and he opted out. This provides a certain degree of freedom to be bold.

Second, the prosecutor who pushed the Swartz case was a Democrat, so you'd expect Republicans to be pushing back. When a Republican Attorney General infringes on civil rights, the Democrats push back.