I contacted some sellers and they sad they opened and closed cases. I counted AT LEAST SEVEN  cases against this buyer.   She is still registered!   Can you imagine any seller with seven cases? I do not.     System treats sellers as garbage. We ever cannot tell what we think - only positive feedback allowed.

So?  It is your choice if you allow somebody with 7 strikes to bid on your items or not; do not blame eBay if you do not protect yourself.

Anyway, eBay is just a website that you advertise your goods, you do all the work, you do your listings and you set your preferences. 

Of-course, buyers have to have more protection; they agree to buy something just going on a photo and the seller's description.  They pay their money and have to be able to trust the seller was honest in describing the item and will post it.  Buyers are much more vulnerable in the transaction.  All what seller is going to lose if the buyer does not pay is bit of listing fee.  Yes it is annoying, but that is a part of trading on the Internet, if anybody finds that so unfair, maybe this is not the place for you.

Actually, I think that ebay is doing sellers great favour by not allowing negative comments for buyers; abusive comments only reflect badly on the seller.  If I see abusive messages left by the seller for buyer in FB or response to the FB they received, I hit the back button fast.