Why were Jewish Defense League extremists allowed at London Israel rally?

”Matthew Offord, a Conservative lawmaker, and Jonathan Arkush, president of the Board of Deputies of British Jews, spoke at a small pro-Israel rally in London where members of a Jewish extremist group were present on Sunday.
The member of parliament and Arkush were photographed on Sunday at the same rally as Robert De Jonge, the Jewish Defence League UK activist who was convicted of assault last year after an attack on two participants in a Palestine literary festival in 2014.
Also at the rally was Roberta Moore, another JDL UK figure. She was initially convicted of assault and possession of an offensive weapon, but the conviction was overturned on appeal.
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