I am happy for all legally recognised political and protest groups to arrange for demonstrations, provided they pass the legal tests. That includes the EDL. I am not the one calling for them to be banned.
In the case you describe, you should be asking Theresa Mays why she banned it, not me.
From the article;
"heresa May banned all marches in Tower Hamlets, east London, and four neighbouring boroughs in the capital for a 30-day period, following a request from the commander for the event, which was passed on to May by Scotland Yard's acting commissioner, Tim Godwin.
The move comes amid fears of violence and disorder if the march was allowed to go ahead.
May said: "Having carefully considered the legal tests in the Public Order Act and balanced rights to protest against the need to ensure local communities and property are protected, I have given my consent to a ban on all marches in Tower Hamlets and four neighbouring boroughs for a 30-day period."
So as reported, she banned it because of fear of violence and damage to property, after consideration of the legal tests in the Public Order act. So on that basis, it seems fair enough to me...