I don't know; it depends how important it is to the site owners. It seems they take a "complete-tolerance" attitude with free speech compared to most sites, and nobody really cares. As long as a lawyer doesn't hand them a cease-and-desist notice, they just let anything through. They obviously do not care about the ramblings of others one way or the other.
I help moderate a wiki with 8 million articles: Plenty of junk appears and disappears. If it weren't for the 400+ mods with a combined knowledge of 60+ languages, it would be an impossible task. The only problem is that comments are only caught by the engine 50% of the time, for some reason. The articles and descriptions are easily caught with the daily database updates.
An internal search engine that catches comment words in YouTube is what it needs; I only read if the comments if I have no clue what I've just seen (which is a very rare occurrence). I assume if the uploader wants to remove comments that have received enough "bad karma", then it can be deleted? But all it takes is a month or so of steady comment removal by searching for key words; after 95% are removed, a periodic inspection every day or so quickly cleans out the rest.
But the owners of YouTube wish to run it their way, so what can you do...except to complain to them?
