"When did you last sit in a church and listen to a sermon that wasn't amplified, even in buildings where people have managed to make themselves heard for several centuries."

Perversely the effect of amplification in such settings is often to make the words a lot less comprehensible. You have sounds coming out of various speakers and bouncing around the hall. The effect can be rather like PA in Railway Stations. They'd often do far better to rely on the natural voice, and speak out. This could be augmented by a microphone, so that people with hearing difficulties could listen on a loop system, but without this being not connected to any speakers.

And the number of times I've heard people using PA in rooms which are easily small enough to do without. The effect is to train singers to use minimal volume, so that they cannot in fact be heard without PA, and this is liable to interfere badly with their ability to produce clear notes at all, because it can be quite difficult to do that when singing very softly. "Sing out" is not just the name of a magazine.

When the volume from the PA is loud, this has the effect of increasing the background noise from others in the room. People tend to feel freer to chatter away, at quite loud volume. Anytime the noise ceases, as when a singer pauses, the voices from the rest of the room boom out.