I guess because to the majority - though possibly not to all Mail readers - the likes of the EDL are simply unacceptable? they may not see themselves as fascist but quite a few do. They are described as a far-Right group, even by Murdoch's media outlets.
http://www.timesonline.co.uk/tol/news/uk/article6790067.ece
'we are not a fascist organisation' they state. They may be, they may not be. seems they are being organised by a BNP member? They are also linked to organised football hooliganism - that took a minute to find out; I guess that's why the police were gunning for them. See their site casualsunited.webs.com where despite the claim of 'no religious hatred here', it's a vehemently anti Islamic site
Freedom of speech however is something that should never be stifled, by anyone. Is a violent reaction acceptable? Not in my eyes. But neither is their threat to carryout their actions in secret to avoid the police... that is a dangerous precedent.
I think I've addressed your questions, but there are more that can be asked. The main one is have they a point? Is Islam becoming a threat? That's possibly for a different thread but has definitely been addressed here ad nauseum.