As TFA explains and other posters have also mentioned, they did not violate any code of conduct. Only the organizers have violated the code of conduct.

A conference for the members of a medical association has the stated purpose of providing a venue for the exchange of information between the members. When the authors of an article published in the journal of the said medical association distribute free copies of that article to their colleagues who attend the conference, they do exactly the thing for which the conference is organized.

Only a shameless liar can claim that such an action is a "violation of the code of conduct".

> All attendees will conduct themselves in a professional and respectful manner, free from any form of discrimination, harassment, or intimidation,” the code of conduct states. “Inappropriate conduct, including but not limited to harassment; threatening or unwelcome physical or verbal actions; or disorderly or disruptive conduct such as protesting, will not be tolerated.”

Which part did they violate?