The author claims that "most of Christendom thinks we ought to be … seeking to convert outsiders to the faith by any means necessary.” How has the prevalence of that belief been assessed?

Whatever the prevailing belief today, the Bible gives compelling reasons to adapt practices and forgo preferences out of love for the lost:
• Jesus said, “[T]here will be more joy in heaven over one sinner who repents than over ninety-nine righteous persons who need no repentance” (Luke 15:7 ESV).
• Jesus took a different form to save us: “Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant” (Phil 2:5-7).
• Paul adapted to better relate to people with the Gospel: “I have made myself a servant to all, that I might win more of them. […] I have become all things to all people, that by all means I might save some” (1 Cor. 9:19, 22).
• The early Christian church was called upon to adapt their worship for the sake of “outsiders or unbelievers” (1 Cor. 14:23-25).