The Niceties Lose to the Necessities
Civility, like anything else, requires resources. U.S. troops in WWII generally did not have to loot to avoid starvation, often had enough manpower to guard POWs, and could afford a training mechanism that instilled and maintained discipline in the ranks. This made it feasible for them to observe a higher standard of humane behavior than most armies, inasmuch as such things are possible in war.
But kindness is a luxury on the battlefield, where survival takes priority over everything else, and first to be jettisoned in resource starvation.
The UK is running low on counter-terror resources. The Times of London reports:
[I]ntelligence officers have identified 23,000 jihadist extremists living in Britain as potential terrorist attackers ... about 3,000 people from the total group are judged to pose a threat.
The British police simply don't have enough men to watch an insurgent army of this size, and have had to cancel famous public events like the Changing of the Guard to release police from duties like crowd security or road closures. "The sad truth about the Government’s decision to deploy up to 5,000 troops on British streets is that it is an admission of failure," wrote Robert Verkaik. In particular, it is a failure to anticipate the threat and to provide enough resources to maintain the required superiority which makes the civilities possible.
Not surprisingly, tolerance has become the first casualty of the new correlation of forces. The smiling British bobby has had to become more peremptory in the face of a deadly foe. British PM Theresa May, in a speech responding to the London Bridge attack, not only announced more regulations (including proposed restrictions on the Internet), but warned that things were reaching a tipping point:
We believe we are experiencing a new trend in the threat we face. As terrorism breeds terrorism and perpetrators are inspired to attack, not only on the basis of carefully constructed plots after years of planning and training, and not even as lone attackers radicalized online, but by copying one another and often using the crudest of means of attack.
The Lone Wolves -- emboldened by success -- are forming a pack, and the lurkers are coming out of the woods to pull down their larger but helpless victim.
When that happens, it's No More Mr. Nice Guy.
May's plan to regulate the Internet has the advantage of being easier to implement than watching 23,000 jihadis. When you can't do what you should, then you do what you can. The West is in the "Three Stooges" phase of terrorism policy: if Larry can't hit Moe, he hits Curley Joe. Later they may in despair all hit each other. To be fair, it's forced upon them by a relative lack of resources. Europe is beginning to admit it has doesn't have enough hard force to deal with the new threats. Hence the reliance on candles, tweets, dimmed lights. It's not virtue, it's necessity. But when the candles stop working they will be forced to Plan B.