How much tolerance should we have for offensive practices?
That's a good idea, and I think things will usually work best if everyone follows "live and let live." However...
Some belief systems are *so* antithetical to ours that we may not even be willing to tolerate. Polygamy, for example--I'm not sure that any level of government has a sound legal basis for outlawing it, but if having only one spouse is the law of the land, how do we respond when Achmed enters the country with 4 wives?
If they're just visiting, tolerating might be viable. But how about if they stay and want to become citizens? Tolerance is wonderful, but if applied in this case it creates a new class of citizens who get the benefit of special rules.
Same problem applies if some sect pops up which has no problem with an adult marrying a 10-yr-old: tolerating this will create a new class of citizens with special rights.
Of course this doesn't mean we *can't* choose this path, but are you sure you *want* to?
We've already seen the nose of this particular camel in our tent: A New Jersey woman accused her Muslim husband of raping her. His attorney countered that such a thing wasn't a crime in his culture, so he shouldn't be held accountable for our crazy laws.
Judge bought it and the guy got off free.
So while "live and let live" is a wonderful principle, making that the standard will eventually bump up against a case that you won't be able to tolerate with a clear conscience.
Why not a different standard: Americans are a very tolerant people, but if you absolutely insist on the right to stone adulterers or flog women who appear in public without a male family member...well, it's a really big world so we trust you'll find a spot more attuned to your tastes--because you're not gonna stay here.