A few of my friends live in Hackney and they haven't been stabbed and there is in my experience of visiting very little more street violence than there is in Brighton for example, also judging Walthamstow solely on police stats is silly, its not the roughest place I've ever been.
In all seriousness, I've grown up in West Hove and Portslade, there is a certain amount of snobiness about it, but with such easy access to Brighton its great, and people talk it down too much. Theres some absolutely bizarre pubs (The Victoria, St Georges) but also some great ones (The Railway...