I don’t believe an argument is a summary. I think it’s more structured, because it’s rhetoric. And so I would argue that while your personal opinion doesn’t need to exist in the argument, it still wouldn’t be an argument just summarizing different positions. You formulate a good argument by structuring the facets of one side of the argument in the context of the opposing side, with having detailed rebuttals for the opposing side’s argument. So in all, it’s not entirely summarizing, but rather comparing and contrasting different points that support your thesis.