when non-musicians lead the hymns

It never ceases to amaze/amuse me when I go to daily Mass somewhere, and there is no instruments, and some congregation member just leads an opening and closing hymn, and I am always fascinated by the range they sing in. I think people pick the starting note as something which is comfortable in their range, (and too bad if that happens to be a high or low point of the song!) but much more often than not, it ends up that the song is transposed down a perfect 4th or even 5th! I have been involved with plenty of arguments about how people complain that the songs are too high so therefore we should teach the people how to sing higher. Um, something is slightly lacking from that argument, I would say. (Mainly, what church musician as the opportunity to "teach" the "entire" congregation HOW to sing?!?!)
So, it seems to me that the obvious solution would be to lower the songs, even slightly. But upon listening to a congregation of non-musicians sing something, it's rather amusing how we argue about whether a particular song should be in C or D or even Eb...let's talk instead about lowering it down so the highest and lowest notes are A! I bet you very few people would feel it was too low...