Even if the person who owns the company is a Christian. Just as with so many religious beliefs, there’s no logical consistency to it.
The same arguments Christians used against interracial dating mere decades ago — see Bob Jones University — are the ones they’re using against LGBT people today: It’s unnatural, it’s not part of God’s Plan, it’s sanctioning sin, etc. Pastors are free to promote bigotry on Sunday mornings.
Now let us make a covenant before our God to send away all these women and their children, in accordance with the counsel of my lord and of those who fear the commands of our God. Half of their children spoke the language of Ashdod or the language of one of the other peoples, and did not know how to speak the language of Judah. Do not give your daughters to their sons or take their daughters for your sons.” Some have claimed the Bible's ban on interracial marriage was based on religion rather than ethnicity, and that the sole purpose of the prohibition was to keep the people pure of idolatrous influence.
This certainly cannot be true in the book of Ezra, where the people put away their ethnically different wives and children.
And again, I would just point you to the decision, which was a unanimous opinion at the Supreme Court, where the Supreme Court said that expression trumps anti-discrimination laws.