Why the the rating is so low?

Precisley: don't look at the ratings, just go and see a movie if you want to and make your own opinion about it.
A lot of films were pannend into the ground by critics, but everybody has his own opinion. So if the critics don't like a movie, then there's a chance that you will actually like it. It's all about personal taste and the way you look at a movie.
So, many people enjoyed Assassins, others didn't. And then you get a low rating like this.
I enjoyed Assassins too, a lot. I gave it an 8.
I was defenitly entertained by it :)

This is a great movie, the start of it is superbly directed and acted out, the contract on the guy in the marshes, then the contract that both men get to get the disabled guy in the chair, I loved his movie and you souldn't take notice of ratings, they are usually the idiotic rantings of the majority, Stallone was excellent in this.

yeah, it wasn't as good as it could have been. I personally don't like Richard Donnar's directing style. 16 Blocks didn't offer me anything better either, but I did like parts of it. Antonio's charactor was the best thing in the whole movie. To me he stole the show. One of the best villians in an action film by far.

Don't get me wrong, he did great on the lethal weapon franchise, I just think this movie had a lot of potential that wasn't met.