Why does Unitarian Universalism say they are a covenantal religion and then do so little with this concept?
The answer lies in the realm of commitment. A strong covenant cannot be experienced without commitment through thick and thin, good times and bad, health and sickness, richer and poorer, until death do us part.
The lack of commitment among UUs to a covenant is well known. It doesn’t take much to join the covenant and it takes nothing to leave. In fact, many people leave and they are never missed or inquired about.
UUs don’t do well with conflict because of their governance model which is consensual and not hierarchical. The root word of “religion” is religare which means “to bind,” “to tie together.” There is very little binding UUs together especially in the face of conflict so they just leave..
Therefore any covenant referred to is very weak to the point of essentially being nonexistent. UUs use the idea of covenant to affirm and promote their seven principles and this affirmation and promotion is rarely referred to and lifted up in any meaningful way in their communal life together.
It is interesting to note that the weakness of Unitarian Universalism is based on its lack of commitment to its basic principles. Some say this is a shame because these principles would improve the welfare of humanity if they were lifted up and practiced more conscientiously. The lack of commitment in any substantive sense to each other in the promotion and affirmation of these principles is the death knell of what might have been a very robust religion.
The bottom line answer to your question John is fear. UUs are afraid of commitment because unconsciously they are afraid of obligations and responsibilities to each other. Therefore they eschew any governance structure that would bind them together in a more meaningful way.