Here is an excerpt from an article
discussing Lewis' feelings about the conservative Christian obsession with homosexuality as opposed to more widespread (and more culturally erosive) sins such as excessive materialism and the drive to get ahead at all costs. Maybe this is because of the tendency, which Jesus noted, for people to point out the mote in their brother's eye while ignoring the beam in their own, as most of the people who so loudly proclaim their Christianity to the world (see Matthew 6:5 – "And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by men") seem to be beset by these very problems.
Lewis also describes, largely in passing, the English public school tradition by which socially powerful older boys enter into sexual liaisons with younger boys, who thereby acquire a status similar to that of courtesans. At one point, Lewis addresses why he has so little to say about this practice, and indeed why he doesn't even bother to condemn it: "What Christian, in a society so worldly and cruel as that of Wyvern, would pick out the carnal sins for special reprobation? Cruelty is surely more evil than lust and the World at least as dangerous as the Flesh. The real reason for all the pother (about homosexuality) is, in my opinion, neither Christian nor ethical. We attack this vice not because it is the worst but because it is, by adult standards, the most disreputable and unmentionable, and happens also to be a crime in English law. The World will lead you only to Hell; but sodomy may lead you to jail and create a scandal, and lose you your job. The World, to do it justice, seldom does that."
Much has changed since Lewis wrote; but one thing that has not is the veritable obsession many Christian conservatives seem to have with homosexuality. As Lewis points out, this obsession has no sound basis in Christian ethics or theology. It is true that Christian morality has traditionally condemned homosexual behavior. But it is, on this view, no different from fornication, or promiscuity, which are also considered perversions of sexual passion, and which draw relatively little attention from contemporary moralists.
Furthermore, as Lewis notes, Christian theology considers lust to be a less dangerous vice than worldly ambition or (especially) spiritual pride. So why are so many Christian conservatives focused on the putative threat that the widespread acceptance of homosexuality presents to the spiritual health of society, as opposed to, say, the threat posed by the widespread acceptance of materialism, or the fanning of nationalistic passions?
Actually, I would have a lot more problems with the specific practice that Lewis dismisses so casually than with a committed same-sex relationship - not because of the homosexuality, but because of the abuse of power inherent in it.