Freedom to be violent

because you disagree with someone?
The CEO of Qantas was attacked with a lemon meringue pie recently. The attack was well publicised. His attacker has faced court on some very serious charges.
It is clear that the CEO, Alan Joyce, is determined to get his attacker the maximum penalty possible. The police seem happy to go along with this.
It should not be difficult to get a conviction. The whole thing was filmed. They know who the attacker is and what his motives were.
In addition to the court processes Joyce has been able to ban his attacker from using Qantas and its affiliate airlines. Joyce says he is "sending a message" that this sort of thing is unacceptable.
Well yes, it is.
Except that another well known figure was attacked a couple of days ago. He was about to launch a book at a restaurant when he was attacked with a mixture of shaving cream and glitter. It was, apparently, done with a good deal more force than the attack on Joyce. 
Yes, it was caught on film too. Indeed someone who appeared to be supporting the attackers was also shown filming it. The attackers apparently wore "hoodies". So far they have not been caught. Yes, the police will "look into it" but more than one person has suggested that they may not get caught. 
Andrew Bolt, the columnist and commentator who was attacked, fought back. He has been criticised for that. 
He may infuriate people - he often infuriates me - but, as he pointed out himself, he has the same right to speak up as someone like Joyce does. Simply because his views are more conservative, not of the left and not as politically correct, does not give others the right to try and silence him.  The media has tried to do it. He has been attacked before in other ways. He has been taken to court. He and his family have been threatened. 
On saying he is fed up with it the response has been, "Well shut up then. Don't say the sort of things you say."
Is that really the answer? Is it right to try and silence someone simply because you disagree with what they have to say? Violence does need to be silenced. Violence is never acceptable. He isn't advocating violence so why should he be silenced? Is it simply because people disagree with him?
Don't we need to get over the idea that only those people we agree with have the right to speak out and speak up?