I guess this is not a topic that is politically divisive, so the judges were free to vote as they saw fit. Which doesn't say anything about how they will vote on other topics, like abortion, environmental protection etc.
To use an analogy: there's people who think operating systems should be microkernels, and people who think they should be monolithic kernels. Windows NT was created to be a microkernel. But around NT 4.0 they shoved the GUI into the kernel space. If you're on the "Supreme Court of Windows NT," how do you view that? One camp might say, "NT is supposed to be a microkernel, get that GUI out of there." Another might say, "yeah but here in the real world, customers demand a fast GUI so it's fine to cut corners."
Constitutional law is basically that, except we're talking about cutting corners with the highest law in the land.