I seriously don't understand how people have problems with these, they're absolutely fine. Not hard to use, doesn't get in the way and you'll never lose them. And if all else fails you can just pull them off, not hard either. You gotta be dumb as fuck to have problems with them.
As with anything else, I'm absolutely certain this is the classic "something changed so I'm going to be mad about it and make up a bunch of reasons why it's bad" thing that happens to every little change anywhere. And what is some tiny inconvenience compared to lessening plastic waste, helping the environment and hurting less living beings? Stop being such spoiled little shits and pull your heads out of your asses.
There definitely is an element of people just not liking it because it's new, but there's also an element of not getting any say in it whatsoever.
Also, they really do get in the way. They make it harder to get a good seal between your mouth and the bottle at any angle, and at the top they hit your nose. They are slightly harder to use, especially if you're using one hand for any reason, including if you only have one hand. Removing them without tools results in a sharp bit of plastic which pokes and irritates your skin.
Finally, this is another patronising effort which makes consumers lives more difficult (by whatever amount) while not doing enough to combat plastic waste.