It's probably not been widely reported because it's barely relevant at this moment, is it? Three men choose to go out and murder a bunch of people - quick, we must hold those Muslim leaders to account before we can fully establish what has happened and what links said leaders have with those individuals above and beyond they abide by the same religion 'in name'!! If they have been shown to be actively attending certain mosques and these specific leaders can be shown to encourage breeding grounds for extremism, then yes, people associated with those institutions should probably make a statement in explanation and be held to account.
And, as already posted, the Muslim British Council have condemned it - so not only is it a completely moot point, the suggestion that they haven't condemned it already is factually wrong.
What would it take to appease you?