I think this is only partly true.
Most of the time new designs come with a few side effects like being really slow or buggy, but then over time those things get ironed out.
For example, the new gmail UI is a nice improvement but it's buggy. Clicking into an email won't flag it as read if you leave the email quickly so you end up with a bunch of unread emails that you actually read which in turn makes me hate the new UI due to a bug. I'm concerned because this was around way back when they announced the opt in beta and it's still not fixed after forcing it on users.
I work for a major UK community site and we get a furious backlash against even the slightest of changes. And sometimes against things that users think have changed but actually haven't.
(Very) generally we as humans hate having to think. Figuring out a change to something we use regularly means all our automatic shortcuts no longer work and we have to start paying attention.
It's like how annoying it is when they keep moving stuff round in the supermarket but *100 worse.
Same. And I still hate the new Reddit. Not because of the new design but because of how slow it is and because they have shifted CPU usage from their servers to my computer.
I've never been like this. I've actually really liked virtually all of the widely panned UI redesigns over the years: iOS 7, every version of Windows, every evolution of Facebook.
However, there have been 2 redesigns that even I didn't like: the Digg redesign, and this Reddit redesign. Both are objectively bad. We know what happened because of the former. It remains to be seen what will happen due to the latter.