[Blasterlord2]

I saw some news earlier that a woman political candidate also was involved in porn.

Just to clarify, porn is legal in the US right not like in Singapore if you are found with Playboy magazine you will be arrested.

Since it is not illegal and person has not broken the law....why is he punished?

I thought it's already properly explained:

Rothman said in an email to the AP on Thursday morning that Gow failed to act as a role model for students, faculty and the community and mistakenly believes the First Amendment equates to a “free pass to say or do anything that he pleases.”
“Good judgement requires that there are and must be limits on what is said or done by the individuals entrusted to lead our universities,” Rothman wrote.