I reject it as a metaphor for all human enterprise, something which is implicitly present in the statement "As a rational being, each herdsman seeks to maximize his gain.". This is merely an ideological statement that may be predominant in some culture, but is not a hallmark of global humanity. It's nevertheless used as one of the major axioms in economic theory generally and this theory specifically.

The main problem is not the occurence of the allegory, but the poverty of the suggested solutions. Even a quick glance at the variety of contemporary and historical cultures of mankind would lead to a plethora of possibilities instead of merely the two exclusively presented by the author (Hardin, not Dil.)

I agree about the mixture of cooperation and competition, but it is clear that cooperation comes first and is even necessary to bring about the conditions for competition. To use a simple metaphor : People see the competing athletes but are blind to the cooperation required for the setting of the competiton, i.e. the buildings, teams, schedules, infrastructure, etc. This myopic view is what makes it ideological. Solid science builds on all data, not a biased selection thereof.