Tommy Robinson was arrested for breaching his parole. This parole caused by his prior arrest in 2017 for contempt of court outside Canterbury Crown Court. So the reason he got this seemingly harsh sentence, was because it was a reoffence, contrary to the terms of his suspended sentence.

The judges correctly found a real risk of prejudicing the jury and like it or not, the UK judiciary take potential infringements on the fairness of a trial very seriously.

A right to a fair trial for others is at least as important as his free speech.

With the gun point I disagree strongly. London has a rate of 1.45 homicides per 100,000 people. Potentially 180 murders this year. This is fewer than most large cities in the US. Most people in the UK don't carry weapons and the rates of murder are significantly lower than in the US. Access to guns increases the ease of homicide. New York has decreased it's rate (although it's still above London's rate) by limiting access to guns.