If it exists, people are going to complain! It's as simple as that. People love complaining about stuff. Some people are just pessimists who love finding things to complain about. And the whole "Squeals are never as good as the original" argument is a common argument that goes with the pessimistic territory.
I use to be like this. When I was young, the only movie franchise that had note-worthy sequels was the original Star Wars trilogy. Others only had fair to terrible sequels. However, it took movies like Spider-man to renew my faith in sequels. So now, I have no problem with them.
Personally, I just ignore most of the complainers, because at least half of them are just haters. If you haven't even seen it or given it a chance, I think you don't have a right to complain about it; I think any argument you make would be baseless and pointless. I think that, if you are going to give a legitimate reason for why you didn't like a movie, then you have to give a legitimate example to back up what you are saying. You can't just say you hate the writing, acting, or whatever unless you have instances where these things fail or weaken; otherwise it's just a generic complaint you could attach to ANY movie, whether you saw it or not.
When I complain about anything, I try to be constructive. Will these measures change my mind about how I feel about movies? Will these approaches change the minds of others? Probably not, but I'd rather be more constructive than a dog barking at the moon.
