[Symmetry]

Well, if you negotiate them stopping and they are centralized enough to respond to a negotiated agreement you can give in to some demands and that'll be that. Sometimes this works (the ends of most wars between nation states, the British agreement with the IRA), sometimes the other side decides to screw you over (see the vikings vs England, Hitler), and sometimes the other side isn't centralized enough that negotiating even makes sense (Al Qaeda).

So there are times when it works and times when it doesn't, but we can be pretty sure it won't work here.