Lots of science out there on them...and as you say plenty of anecdotal reports for as you say whatever that is worthIm not a big believer in uv, but that is more opinion than fact as I don't see a lot of evidence either way.
People saying it works for me really doesn't give any evidence at all, you might say it works because ive not got ich, that's fine but who is to say you wouldn't have ich without a uv steriliser, the same for people saying it didn't work for me.
There needs to be a lot more scientific testing and support rather than anecdotal to know for sure.