I have to wonder what parts of the internet you regularly inhabit for trolling to be colored as "generally harmless if not annoying as hell" as opposed to "just offensive, dickish behavior and I personally think people who do this shit should be banned from whatever websites they're doing it on." When you have something open to the public, there will always be dicks. Combine that with anonymity, freedom from immediate repercussion, easy access, and less stringently enforced social graces, and that number will be upped to the nth degree. The only advice I can give you is to treat it like white noise and to avoid baiting them.
Also, after wading through those youtube comments you mentioned, I can say that I find them marginally more distasteful than the crop of "tribute" videos springing up in the animator's wake made by people not even remotely connected to him in what I can only describe as a shameless grab for sympathy internet-points. Nothing quite like capitalizing off of a man's death for a free ego boosts, is there? (See the Steve Jobs tributes and 60% of DeviantArt journal entries)
Captcha: "face the music". Oddly fitting.