The words of well known carols

A little flurry of messages from friends distressed by being presented with rubbish words at advent carol services round the world alerts me to the fact that the creeping habit of ignorant and offensive interference has now become so prevalent that even the words of things everyone knows off by heart are being messed up. Now what is the point of that? If people really know the words by heart, then either they will blithely sing what they know and you might as well have printed that in the booklet, or they will be upset that the words don't mean what they should mean, or you will draw attention to things that are not in fact offensive and misleadingly give the people to understand that there is something wrong with them, so that they'll then be worried by them when they meet the proper words on some later occasion and will come to believe that those who sing the real words are corrupt.
Tenon-Saw reports on the carol service from Clare College, with comments on their badly adjusted version of Hark the Herald Angels, here. Annie has sent me a puzzle about "On Jordan's Bank" which I will need to investigate, but it looks like the unfamiliar version is actually the more authentic one in that case (which is actually the theme of several posts I'm about to work on, so watch this space).