This actually violates Larian's own design philosophy. There should be multiple ways to complete every quest.
And although "kill everyone in town" is an option, there should be a third skill based one.
For example, if you fail the diplo check you can ask to "rent" or "consult" the head for a ridiculous fee paid to the performer.
Paying said fee allows you to talk to the head without coming across as a felon.
