[God Emperor]

Its an AI thing. Non-peaceful races seem to have problems with unhappiness.
My observations (v127) were that neutral and bloodthirsty races didnt seem to like treaties of any sort and even the most aggressive AI races need to establish some treaties (or be overwhelmed by their neighbours).
The way bloodthirsty should be handled I think is that the race must be at war with someone at all times, but, as long as that condition is met it should not be penalised for having treaties.
Neutral races should only care I think if peace treaties get broken or wars are unsuccessful.