The most important part in that community would be the leader. In way like despot or monarch, the clan members will entrust their survival to a leader who they believe know better about how to keep everyone alive. And since they have entrusted themselves to this leader, the yukkuri need to follow the clan's rule, because they have chosen their leader and relinquished part of their freedom in exchange of safety.
About the hierarchy of priority, true. I'm just addressing the last part. Like in human, there are many reasons for someone to be nice to others. Common reasons being: because it's what's expected by the rules (law, tradition, religion, etc), in expect of favour (building public image, making debts, gathering karma point buy ticket to nirvana), just selfish reason (it made me feel good), or no good reason at all (never thought about it, but that sounds like a nice idea at the time)
IMO, the last two are the most simple and shallow reason that would easily be applicable to yukkuri.
Also we did saw sample of Shitheads not eliminating the last part of making others feel easy. It's just that their megalomaniac mind thought their presence is making others feel easy, but they just don't feel easy with the mere presence of other lesser yukkuri, so they expect others to pay back more.