Personally, I believe that the quality of writing should be judged by people that in their own right are quality writers, not just writers who write. That means actual authors of books who never used a vanity press to publish anything or Hub moderators who are paid to do so.
With that said, I am not an actual author or a Hub moderator, so I don't feel qualified to judge anyone's writing.
I will however rate an article based on how much I enjoyed it or learned anything I didn't know before I read it. I never give a negative rating. If someone offends me, I just don't engage with that person because no matter what that person is writing about or how they wrote it, whether or not they stereotyped or over-generalized or even name called, it still remains their opinion. They are using their right to express themselves. You don't have to like it and not everybody will. That's the beauty of freedom.
For me to give them a negative rating, would mean I don't agree with them. And? What was I trying to tell them with my "thumbs down"? I don't like what you wrote? So? Why would they care? They still got you to read it. There is no solution because there is no problem.
And for those of you who may be wondering what's the point in not rating negatively, I ask you the same question as to why you do. It's not our job to judge anyone on their ethics here or in what form they choose to express it.
If you don't like it, you move on to another article. Let the moderators do their jobs on taking care of those that you find offensive.
Not everybody will agree with everything you write about. You will always find opposition. And with that said, maybe it's just a matter of how you handle critique. That's my opinion. Yikes, hope I don't get a thumbs down for saying that or putting a smiley at the end of this sentence. :)