Religion is the main cause of wars in this world. It's good to mention it in the songs once in a while.

Perhaps that is the case in America.  But in India, there is certainly a separate category referred to as devotional music, which is basically songs in praise of God(s) and it's identified as such in record stores.  They may not specify HINDU devotional music but there's no need to as all the titles stocked by the stores in that category pertain to Hindu religious music.  And as far as I know, Christmas music is a distinct category over there and it's a bit difficult to argue that that has nothing to do AT ALL with Christianity because it is a Christian festival.  We do have Christmas holidays here because it's a sort of festive season and we treat ourselves to pastries and all that but we don't say any prayers because, all said and done, it's not OUR festival.

This.  At least so long as the music is not a vehicle to further a hateful and violent agenda.