He converted when he was 30, which explains why he may have some writings expressing a dislike for several religions. He wrote Screwtape as a Christian though, so you may be mistaking Wormwood's views for Lewis', it's harder to tell what is satire in that book. He didn't like some of the theology of Christianity, but was very devout, as is plain from the Narnia books and many of his other works.LimaBravo said:As far as I know Lewis loathed organised religion -
His conversion is very interesting, well worth looking up.