I should probably add volor.about 2 more things:
(1) there are many factors that determine how a video performs in the algorithm. likes and dislikes play a part in the algorithm, but its a small part relative to other factors such as whether someone stays on youtube after watching those videos or leaves youtube (the latter being bad for youtube, cause the algorithm doesn't want you to leave)
(2) another way likes and dislikes come into play is that it tailors the experience for the watcher. so in theory, a troll thumbing down tells the algorithm not to autoloader more videos from that channel or similar type videos. but if the trolls are subbed, and they watch ever video and comment on every video anyway, that behavior outweighs the thumbs down
basically, if the artificial intelligence was alive, it would tell trolls "yo. you are embarrassing yourself. find a hobby"