1. No one would infer that the design was done to keep homosexuals from being married, but the overall design was to not impose the state on religious practices. 2. "Should" is subjective.  The church is not "immune" either, however keeping the state out of religious affairs is a longstanding and effective practice to order. 3. And if the state defines what "Catholicism" is, then yes they will be prevented from practicing religion as their churches define it.  Anti-social behaviour is