I don't think the BBC and these types of 'academics' realise the fire they are playing with. These kinds of comments do not endear ordinary English people to multiracialism and diversity, they have precisely the opposite effect and ultimately just drive more of them towards the far-right and further entrench those who already hold such views. If you constanty criticise and belittle the culture, traditions and symbolism of a people and their nation, then don't be surprised when they despise you for it and rightly see you as a threat to their identity.
Just a few points, the Crusades where not the one way street he seems to portray them as. They were in large part a defensive response to several centuries of far more brutal Islamic aggression and conquest towards Christian lands. And it wasn't St George's cross that flew over the Empire and the colonies at it's greatest height, it was the Union Flag, why doesn't he take issue with that one? I wonder if he would also take issue with the Turkish flag for example, which stood as a symbol of Ottoman imperialism, oppression and enslavement across the Middle East, South East Europe and North Africa for centuries? I doubt it, in fact I'm certain if he pulled the same cards in Turkey, they wouldn't be anywhere near as tolerant towards him as we are here.