Most anybody can say why they hate it, or why they like it. This topic can be debated forever along with the numerous other additions come out. I think all the variables haven't been explained yet.
If what the topic explains, that those that started playing DnD prior to the release of 3rd edition, have a dislike for the fourth edition. You could just summarize that into the category, of play experience. Those that started to play prior to the 2000 release, haven't been exposed to the game long enough and all the elements of the prior edition to form an opinion of that edition. So that leaves alot of newer players switching to 3rd edition. That rules out second edition entirely, now take 3rd edition, new player exposed to that era would have a remarkable amount of experience of play. Then all of a sudden out comes 3.5, which is has its differences but easily adaptable. The same as 1e was to 2e, very easily adaptable.
Not 4th edition, not adaptable to any other addition, so any experienced player would have to learn a whole new system over again. But players have been doing that for years. Supplements and rulebooks changed over the years. Editions changed and some were adaptable others were not. If anyone ever changed from second to third edition knows that it is a lot of work, taking an existing world in a previous edition and adapting it to a newer edition.
My opinion is that, with the years 3rd edition has been, you have gamers out that designed their own campaign, game worlds. Used these creative juices, to improve on the rule set given and with the ever increasing editions takes an amount of effort to let go of this wonderful thing they have produced from there own mind. Because most additions were easily adaptable, that it was unnecessary to change large amounts of information to convert over to the new game system. Not only would the all statistical elements would change, i.e monsters, NPCs, PCs etc., but also the story element will have to be rewritten to reflect all the changes imposed.
I saw a post earlier about a water craft and the differences imposed earlier. All those differences have to reflect throughout the entire story so not one element changes but all.
I don't think it is hate, that keeps most players from trying 4th edition, or a newer edition. I think it is those that have created something, or are happy and have fun with that they have and enjoy it all the more because it is there creation. If a new player has run the same character since 3rd edition made its debute, and is still in an ongoing adventure, where millions of possibilities exist.
To be blunt about it, I think that players who don't switch are happy with what they have and are more willing to see it through to its end, before the possible switch would take place. I know i didn't switch from second to third until 2004, when demand new material made it an obvious choice, but as a group we were equally happy running those second edition games just as eagerly as we were for the new material. But when it came time to switch all our existing material, we mine as well had started over from scratch, and the time we had spent on it before hand had seemed just a wasted effort.