Sociologist: Romantics who claim that people are not born evil but may be made evil by the imperfect institutions that they form cannot be right, for they misunderstand the causal relationship between people and their institutions.
Conclusion
People are not made evil by the imperfect institutions that they form.
Intermediate Conclusion (for)
Romantics misunderstand the causal relationship between people and their institutions.
(Romantics think that institutions cause people to be evil, so if the author thinks they misunderstand the causal relationship, at a minimum she is saying "institutions do NOT cause people to be evil", which is essentially a reiteration of the main conclusion. She might also be insinuating that in reality EVIL PEOPLE cause an institution to be bad, but we don't need to go that far, since her premise isn't directed towards proving that sort of idea.)
Premise (after all)
Institutions are merely collections of people.
Evaluate
The main and intermediate conclusions are essentially the same claim: institutions don't cause people to be evil.
And this is based on the claim that institutions are just collections of people.
Goal
If we're prephrasing a typical "if evidence, then conclusion" principle, we want something like,