Honestly, I have never seen such a hatred for a series in a fanbase before.
You must not have been around long, then. A decade ago, the vitriol toward
Enterprise was just as hateful, and tended to hit most of the same notes. There was also similar negativity toward TNG in its early years, and there have been decades of fan negativity toward ST:TMP.
I wondered whether I should type this, but I am sincerely quite perplexed. It's a question I've been wondering for a long time. Why is the hatred for the reboot series so vocal?
Because there's always going to be a minority of people who really hate anything outside their comfort zone and are determined to broadcast that hate so loudly that they drown out other voices and create the false impression that their views are widespread (particularly since they constantly insist that their personal opinions represent the consensus of all true believers everywhere). This is as true of fandom as it is of religion or politics or anything else. (Just look at the physical riots that break out in soccer fandom.)
There was a guy a while back named James Dixon, an obsessive uber-fan who became so devotedly attached to the version of the Trek universe that fandom established in the '70s and early '80s that he simply could not tolerate it when new productions like TNG came along and contradicted his deeply held convictions. He spent the next couple of decades denouncing all new Trek with the kind of fervor generally reserved for war crimes and acts of terrorism (even as he continued to meticulously record and chronicle every new episode, film, book, and comic, crafting one of the most obsessively detailed chronologies ever created). He used to be a member of this very BBS, long ago, and I had my share of intense debates with him. He eventually got banned, I think, and he vanished from the public eye quite a few years ago. Which may be just as well. I shudder to contemplate the toxic verbiage that he might have put forth about the Abrams movies.
And it's not just Trek fandom. Back in the '90s, I was on a local BBS, one of whose members had an intense, religiously fervid hatred for the 1996
Doctor Who TV movie, damning it for its inconsistencies with what he imagined to be the original series' continuity, ignoring the fact that the original series had had very little continuity and had changed enormously over the 27 years of its run. And his hatred never died down. When the BBS shut down a few years later ('99, I think), in its final hours of operation, this guy posted a farewell message that was simply a restatement of his unrelenting hatred for the
Doctor Who movie. Three years on, and it was still his overriding obsession -- and his ego demanded that he get the last word.
So there have always been people this hateful about new iterations of fictional franchises. It's just that as the Internet has spread, it's become easier for them to be heard more widely.