It's perfectly fine to say you don't like it. I hate MK's PotC. There. I'm not a pixie duster.
The difference is when the reason you give is self-contradictory or you have strong dislike for trivial reasons or you tie it to a hatred of something else (Iger is the devil!!) or you just out and out make up spit like saying this has less fireworks than Wishes, which is not true at all.
So, some people are indeed getting a hard time for expressing a minority opinion, it's just that when the minority opinion is backed up by stupidity, then that is what's being attacked.
Note the people who are saying they liked Wishes' storytelling better... they're not getting attacked for that. Wishes had narration linking each segment, HEA doesn't. Valid point.