Because I had a bad experience, it didnt work in my instance. I upgraded my project for the plugin, it didnt work, you closed the bug report aka saying this issue is resolved when it fact its not, and also i tried to setup a fresh wordpress and it still doesnt run. it made me a bit frustrated, so i think it deserves a bad rating, speaking for my own experience with the plugin.
When the plugin works again, or you keep a bug report open to follow progress or something like this, my experience may change and I change my rating or make a new and better rating.
Please try to think from my side of things.