Did they also decline a request for AVE MARIA of which Andy Williams also did a fine version, or THE HALLELUJAH CHORUS?
I don't know, because I don't know of anyone who requested
Ave Maria. Likewise, I don't know anyone who might have requested
The Hallelujah Chorus. However,
The Magnificat is based on one of the few psalms in the New Testament and is sung while Mary is expecting Jesus. That makes it an Advent season song, ideal for pre-Christmas music.
Ave Maria is rather generic in terms of the church calendar. Both the psalm and the prayer have have been set to music by many composers, and recorded by many artists. Both are part of the Roman Catholic tradition, which many of us Christians regard as part of our extended religious heritage.
I disagree with anyone who would reject playing a musically appropriate recording of
The Magnificat at Christmas time as "too Catholic", but I wouldn't strongly disagree with anyone who would reject playing
Ave Maria as "not Christmas music". As for
the Hallelujah Chorus, it was written by a Lutheran for performance in an Anglican country, so the "too Catholic" argument holds no water at all. It's commonly performed around Christmas and Easter, as well as other times. However, unlike the other two songs, there are no versions of it that fit any usual radio format. There are plenty of recordings of
The Magnificat and
Ave Maria that would fit with the rest of the music on a CCM, country, or even CHR station. That's not the case for the Hallelujah Chorus.
I've been in choirs that sang
the Hallelujah Chorus several times, in several venues. I sang it in high school, in several churches, as the finale/curtain call for the rock opera Jesus Christ, Superstar, and as part of two different flash mobs. Even dropped down to the more tenor-friendly key of C, it's a magnificent, powerful piece of music. But, I can't imagine most modern commercial radio stations playing it.