In game theory and mechanism design, there exist dominant strategies. This is an objective truth, and exercising the dominant strategy is objectively better than not.
The earth orbits the sun. This is an objective idea. Fighting against the notion is objectively a bad idea.
Elephants shouldn't come in my house. I value it not destroying things in my home, etc.
You shouldn't deliberately reuse GUIDs as an IDs for things that are different.
Relativism is certainly something that exists, but it shouldn't be universally applied that all ideas are of equal value in all situations.
Socially, sure, use relativism when listening to ideas before coming to a consensus. That doesn't mean all ideas work, only that all ideas are given the same treatment. But bad ideas exist, as do good ideas.