I ripped a 3D Bluray by expanding the title and checking "3D Video MVC" (or something to that effect, I forget exactly). Then I opened the MKV file in sView. I set the Stereoscopic Format to Source, selected Anaglyph Glasses and set Glasses Type to Red-Cyan, and Red-Cyan Filter to Optimized. It works!
If it matters, I'm using openSuse Leap 15.0 and installed sView from the Packman repository.