An attack on London is an attack on multiculturalism, not the "imperialist West" or the "crusader states." The great irony is that it is highly likely the diverse victims of the Westminister terrorist would have either met his demands or permitted him and his kind to implement them in the long haul. Liberals never say no to spread of Islam, so there is no reason to use violence to dominate them if you are a Muslim. You need only wait and take the Houellebecq or the Boumediene approach.
Multiculturalism, because of the premium placed on tolerance of all things colored, must accept the intolerance of puritanical Islam. In fact, this tolerance tends to increase after terror attacks because the press reminds the people that "racism" is the real problem in society and that Muslims are the true victims (and therefore deserving of sympathy). Attacks are not even necessary to create this narrative however, since anything remotely self-interested that White people--whether British or otherwise--do can be framed as racism to reinforce the aggressor-victim paradigm. No action is required on the part of people of color, since the paternalistic implication of multiculturalism doesn't grant them any agency.
More important to the absurd unnecessity of the latest jihadist attack is that it technically took place in the Dar al-Islam. London mayor Sadiq Khan is a Muslim. The city targeted is governed by a Muslim. It is theologically-speaking, Muslim territory. Of course, Muslims attack one other quite frequently over their Mosaic distinction, e.g. Syria, Iraq, Afghanistan, but this disunity only harms the cause of jihad in the net. The City of London, and generally speaking the larger British state, are among the most philo-Islamic governments in the world.
Do not be fooled by the American election of Trump. That is not Europe. We live in a timeline where one shouldn't be surprised to see a Prime Minister Sadiq Khan, who will go on to be one of the most popular "European leaders." That is certainly a plausible trajectory and it requires not an act of violence on the part of Muslims in the country whose police forces tolerate foreign rape gangs that go after their children.
Jihadist attacks against London are friendly fire. When you can butcher the Franks in their capital cities and your kind receive net sympathy from them, they are not your enemies. They are a conquered people and you are being unnecessarily cruel by slaughtering them. Your own religion tasks you to treat your slaves better than this.
This message will be lost on the Islamic colonists--that all they had to do to win was vote and breed, not fight--but I suppose they remember Europeans differently than Europeans do. But perhaps, once the last tolerant European has died in the name of diversity, only the intolerant will remain.