[Mia T]

If I were forced to assign a label to you, it would be "accidental deconstructionist." --me

Rather easier than actually refuting me, isn't it? --you

You asked for nuance ;) … I agree with you that "relativist" didn't quite cut it.
Rather than repeat myself…again, I will paraphrase Boswell. I did refute your argument , but I am not obliged to find you an understanding.

[Mia T]

They are doing exactly that, except that it's logically consistent within the rules of the system in which they operate

Okay, one last try:

You are missing the essential point.
The system to which I refer is a result of evolution, not personal preference.
The rules describe the invariable bias of humans in favor of self-preservation
("Survival isn't chocolate ice cream." - Get it, yet?)
The rules are encoded in our DNA.

The behavior of radical Radical Islam is inconsistent with those rules.
Radical Islam's behavior is irrational.
QED.