So, here is a handy guide to whether or not you should consider talking to terrorists, all you need to do is answer some simple questions.
Q1. Is it your job?
What is your primary job, is it:
(a) representing constituents and voting in Parliament, or
(b) joining up a wide variety of minority interest groups and meeting people with unpleasant views in far-flung countries?
If your answer is (a), why are you trying to "engage" with terrorists, instead of doing what you're paid for?
Q2. Are you partisan?
(a) only talk to one side, or
(b) talk to both sides?
If your answer is (a), how can you possibly be useful as a diplomatic channel?
Q3. Do you condemn all sides equally for atrocities?
When you do condemn, do you
(a) condemn one side universally but only condemn your favoured side when you have no other option, while simultaneously saying "but what about the other side doing XYZ"? or
(b) condemn both sides equally and fairly for atrocities?
If your answer is (a), how can you possibly be a useful diplomatic channel?
Q4. Are you qualified?
Are you (a) a senior politician or (b) a very senior official?
If your answers to (a) and (b) are no, you are probably merely a fool, legitimising some dodgy person/regime. A "useful idiot".
So, you are now fully armed. Just in case you should be someone with pretensions to be an amateur diplomat, suddenly thrust into the limelight with an unexpected possibility of leading their party, you'll know what to do.