But frankly I don't understand why "Twitter abuse" is seen as such a big problem. In general if you wish to publish something and provide a channel for people to respond, it's practically impossible for anyone to guarantee you'll be happy with all the responses you get. This is one of the hard parts of being a publisher, which is what you become when you sign up to Twitter. It's sad if someone is hurt by the responses they receive, but it's not really Twitter's problem. Twitter does provide ways to shield yourself from hostile and abusive users but the expectations being placed on them seem unreasonable to me.
It's interesting that this exact same conversation is going on about Reddit (how people are offending each other, and we need to "fix" this). It's as if no one grasps that this has been going on since the beginning of time and if there's more of it at the moment that might point to a deeper problem in society which needs to be resolved through dialogue.