When you and someone else identify yourselves as married, it's not like saying "we're lutherans" or "we're catholics," where everyone can either agree or disagree whether you're really lutherans or catholics. When you say you're married, everyone has to agree with you.
They have to agree that you are legally married, but they are in no way forced to accept the marriage in a spiritual, religious, or moral sense. That remains an individual choice.
For example: I'm sure there are (unfortunately) many in the US that still refuse to accept interracial marriages as valid on moral grounds.
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