In no way does the article suggest that the attack is "the tip of an Islamo-fascist iceberg". Nor does it moralistically exhort "non-fundamentalist Muslims" to speak out or condemn them for not doing so. It makes a very simple point - a worker was attacked by religious reactionaries, on an entirely reactionary basis, and the left/labour movement has said nothing. This is bad. End of.
The religious right is a very significant force in the politics of Tower Hamlets; for sure, the people who carried out this attack are not representatives of the "official" religious right or of any mosque leadership or anything similar. But the labour movement's failure to comment on the incident helps contribute to a situation where the hegemony of right-wing religious politics over "the Muslim community" (which I agree does not really exist in the sense that either the Daily Mail right-wing or indeed the mosque leaderships want it to) is never challenged.
The East End of London has seen this all before; in the early 20th century, the revolutionary left was absolute clear in taking on and challenging the hegemony of the conservative synagogue leaderships over the Jewish working class. Presumably you wouldn't have accused Rudolph Rocker or the ILP of implicitly chiming in with anti-Semitism?
I think you're manufacturing controversy/disagreement where there is none.