Final answer:
The mainstream definition of sustainable development promotes consensus because its vagueness allows stakeholders with diverse interests and values to support it without contestation.
Step-by-step explanation:
According to Lele, the mainstream definition of sustainable development is so good at building consensus because it is too vague to be contested by stakeholders. This vagueness allows for the alignment of diverse stakeholder interests and values since it does not rigidly prioritize one set of concerns over another. Rather than clearly defining specific goals or standards, this formulation of sustainable development allows different parties to see their priorities and values reflected within a broad and inclusive framework, facilitating agreement and cohesive efforts towards a common goal despite varying perspectives.