Well, my background is in signal processing, control theory/feedback systems, and instrumentation. Someone's noise is another's signal, and vice versa. Processing and filtering, with the best of intentions, comes at a price. Tradeoffs, ah, tradeoffs.
Looking at Reddit‘s /r/askscience I‘d heavy moderate. I‘ve seen threads where more than half of the comments were hidden. I think /r/askhistorians is similar.
First, you must define signal and noise. That is a very big problem.