He, as alas many if not most American Christians, is weak on the gospel. The gospel tells of a God who will BLESS to sexual integrity. We hear almost nothing about that next to countless repetitions of Leviticus, which are true enough but if you stop there that is only half the story, and not even the most useful half. Without that important part of the gospel there really ISN’T any compelling reason to call homosexuals up short any more. Might as well they go to hell because they can’t be brought to heaven! God weeps.
Let me mention too that this half-gospel is dangerous in that people can indeed accept Christ for salvation, but because nobody has assured them that they can in fact count on being able to rest on a forgiving (not excusing, forgiving) and empowering Christ, they instead launch into that Christian walk resting on pride. And some do it for years and they are spiritually emaciated and see little victory. I know! I have been there and done that! On the other hand, resting on the love of Christ, even if the result seems embarrassing at first, will quickly engage the power of the Holy Spirit, and wonderful victory AND a very close omnipotent presence of the Lord will be seen.