In a society, collective objectives are preferred, rather than decisions made by a single individual due to the desire of every human being to have their thoughts considered. Therefore, a collectively implemented code of ethics would satisfy the preferences of many, and it would be even easier if most of the implementers had similar ideologies.
An ethics committee would further improve the efficacy of the code, as the committee members would be in charge of updating the statutes in order to satisfy upcoming needs as society grows and evolves.
While single-handed leadership may work on ensuring the prosperity of a company, when it comes to ethics considering what other people deem as righteous is important to keep moral balance, as morals may vary on each individual.