Well, the line does go "...and no religion to" and even if we're just being asked to 'imagine' it's clearly put in the light of "oh wouldn't it be wonderful". So there's a chance some kids would wonder why they can sing that as part of a church singing?

Now I'm not English and I'm not Christian so I clearly could be missing some nuance of life that puts it that the Church should just 'ignore it and go on'.

The types of Christians I'm more familiar with would have simply left out or changed that lyric and gone on with it.