How can you be harassed by someone who has actively sought to prevent all contact?
When someone creates fresh accounts after being banned, and carries on postIng about another person, by name, on a public platform, where anyone not specifically blocked (or simply not logged in) can read, share, and circulate, that’s not avoiding contact is it?
Blocking someone, so they can't read your tweets and you can't read theirs, is the definition of avoiding contact. There would, self-evidently, be no direct contact at all unless one side actively sought that contact. It doesn't mean the other isn't allowed contact with anyone else, or must remain silent.
That’s just talking about someone when they’re not directly in the conversation, whilst knowing that they will hear all about it one way or another, as will literally anyone else who cares to look, or has it shared to them.
I wouldn't know what someone said about me if the mutual dislike was sufficient for mutual blocks, because I'd block for a reason, not to make a flouncy point, and my friends have sufficient maturity and common sense not to take pleasure in shit-stirring. And there is no right, in life or in law, not to be talked about. There is a right not to be harassed, and a right not to be defamed. You can't be harassed if you have to seek out the discussion. Every gossip site on the internet would be liable, were that the law.
The prosecution, according to the reports, argue Kate created multiple accounts to circumvent a block. Yet now it seems that she created those accounts to avoid Twitter rules, not a block from Hayden, and in fact had blocked Hayden herself. Hayden's confusion in believing retweets were visible despite a block does not make that true: it is not true. Nobody here is arguing that it is true. Hayden sought the tweets out; they could never have been seen otherwise.
This is not complex or esoteric. It's very simple. If you don't want contact, and don't want to know what is being said about you, don't take active steps to find out.