Ref Dead Horse's comments --- Steve P is quite right --- merely being old and well-loved does not make anything safe from criticism (I know this because people have been known to criticise me!) On the other hand, there are wellknown traditional ways of dealing with this situation. 1) Ignore it --- nobody who likes the song cares about what anyone else thinks. 2) Rewrite it so that you like it. Nobody else will, but you'll be happy.