Your question makes me feel like crying, secondimage. It is so disheartening to hear that any hubpage participant would be abusive to another. After all, we are all in the same boat, with a love for writing. Anyone with "Best Seller" next to their name would be busy publishing their latest endeavor, with little time left for the hub. And, ironically, the best writers understand the "hit and miss" even among the professionals. It is not likely that the cream of the crop would be mean, as they know firsthand, the difficulty in becoming a highly successful author.
I believe the best defense is an eloquent offense. Disarm abusers and bullies with your charm. (I can tell from your question that you are a sensitive, kind-hearted writer, which makes you charming). Although, it is easier said than done, if you can develop a sense of "I'm O.K., You're O.K.", dismissing differences for just that, you might be able to begin a personal process that thwarts the confidence annihilating effects of abusive commenters. Try not to take it personally, secondimage, as those personalities often have a long history of abuse. Lessen their negative impact by thinking about how grateful you are that they are not part of your real life. That idea helps to make it easier to dismiss them. If you see that a bully is persistently invading your space, flag them.
Sometimes it helps to know that if a reader isn't pleased with what you offer, they normally don't return. Just like a store you visit with prices beyond your means or substandard quality merchandise leaves you feeling; do you go back? This can help you realize that the particular individual employs bullying to feel powerful. Sad agenda, but it happens.
Don't stop writing because of a few dysfunctional participants. You have the same rights and are just as important as the next guy. In fact, it is our differences that make the world an exciting, unique and always surprising place! Stay strong, secondimage.