Isn't it strange?

Rating: 10/10 (2 March 2005)

Until recently this board (or list of comments) was full of posts appreciating and praising many virtues of this movie. Then suddenly some people appeared out of nowhere and started to badmouth Oldboy, and they got many supporting votes.
Now, the natural trend came back and more comments are positive about it, but still they are consistently getting 10-30 negative votes. Who are these people? I mean, who would regularly visit the site for a movie they so hated and keep expressing their disappointments by pressing 'no' button for every single pro-Oldboy comment? I am not trying to say the movie should always get positive feedback. Oldboy is obviously not for everyone, and some people have to dislike it. I'm OK with that. It just looks so unnatural that almost two years after debut the movie suddenly created a well organized - it almost seems that way to me - group of haters who dominated the opinions for more than a month when it has been receiving over 8.5 rating from the average visitors so far. Could there be any reason not disclosed here?