No they don't just hate him because he changed Star Trek. But because he led Star Trek to a very different path und changed Star Trek INDEFINETLY.
It would be naive to think that the JJ movies don't have a lasting effect on the 'original' universe. The last Star Trek movie was a shiny, full-of-action, over the top teen movie that made a lot of people go to the cinema who never watched Star Trek before. It's only logical to expect the next JJ movie and a potential new series to be of the very same kind.
Most of what I liked about Star Trek in the past won't translate into a new movie or a new series. For me Star Trek is about social criticism, interesting technical and environmental phenomenons and the peaceful overcome of obsticles (despite the Dominon war). Nothing of this could be found in the last movie.
It's naive to think that an alternate universe version of Star Trek (which JJ's movie was), changes the original in any way, imo There's a reason why they call it an alternate universe... because other than the cutoff point, they don't share much in common. The original goes in one direction in the timeline, while the new one continues at the same rate in time in a different direction.
Which is the point: the Star Trek that you love, still exists. The new Trek, embodied by this movie, will go on regardless. They're completely seperate, even as they're the same name of a franschise.
Blaming this new Trek to be changing Star Trek indefinitely, despite the fact that the original still exists and is untainted, because this movie is seperate from it... I find that illogical of many people, personally.