"The overarching aim of Islamic terrorism is to drive a edge between Muslims, all Muslims, and the West. The principal counter to that aim, therefore, is not to fall for this. That should be common sense, I'd have thought.".
I've seen this point made many times, Jim. In fact it's the stock reaction to these atrocities, isn't it? Here's another even plainer version of the point you're making:
" Whatever twisted motives these people claim to be murdering for, it is quite clear these atrocities are designed to sow division, and create hatred and distance between communities. We cannot let them succeed.".
We get a "twisted" and a "claim" in in the first clause, but an "it is QUITE clear" in the second.
As I know you're far from lazy-minded what makes YOU so sure that driving a wedge between all Muslims and the rest of us is their aim? What do you think is in it for them?