You make a fundamental error here by assuming that he was attacked because people support Hamas, that may or may not be true. It isn’t a given. It does show they have responded with violence to a statement that offends them.
In response to your question's, I clearly explain my reasoning in my original post, please see below.
Regarding Niyak Ghorbani.
A factually correct sentence can take on a different meaning depending on the context in which it is presented.
So for instance while it is factually correct to say ‘all lives matter’, if somebody were to attend a Black Lives Matter protest while holding a sign saying this, you could infer that they were actually a counter protestor, or at the least trying to diminish the aim of the protest.
If somebody were to attend a protest for the hostages while holding a sign stating how many children had been killed in Gaza, it would have the same impact.
So by the same reasoning, to hold a sign saying ‘Hamas are terrorists’ implies that people need to be reminded of this or that people are marching to support Hamas, which is unnecessary and inflammatory. It can be interpreted as an attempt to detract from the main aim of the march, which is to advocate for a ceasefire and freedom for Palestinians.
Either way the point of my post was to highlight that I don’t need to agree with what this sign says to support his right to free speech, to believe that he should not be assaulted, and that he should be treated fairly by the police.
I’m not sure I genuinely believe that posters are unable to understand that the meaning of a sentence depends on the context in which it is used.