Sigerson argues that the city should adopt ethical guidelines that preclude its politicians from accepting campaign contributions from companies that do business with the city.
Conclusion
Sigerson's proposal is dishonest (i.e. he doesn't really think that the city should adopt ethical guidelines that preclude politicians from accepting campaign contributions from local businesses)
Evidence
During his career in city politics, he took contributions from such companies.
Evaluation
This is the famous flaw Ad Hominem, in which an author dismisses someone's view because of that person's biased interest or because of that person's conflicting past behavior/statements.
It's possible that Sigerson learned from his own mistakes about the unsavory conflict of interest of accepting contributions from local businesses.
Goal
Look for an answer that says our author dismissed a view because of past behavior, or one saying that Sigerson may have accepted contributions in the past but nonetheless genuinely feel it is a bad thing.