The post I was replying to did not specify on the ship. It was made in general terms. My response was also in general terms.
Yes, it is legal discrimination.
From dictionary.com:
dis·crim·i·na·tion [dih-skrim-uh-ney-shuhn] Show IPA
noun
1.
an act or instance of discriminating, or of making a distinction.
2.
treatment or consideration of, or making a distinction in favor of or against, a person or thing based on the group, class, or category to which that person or thing belongs rather than on individual merit: racial and religious intolerance and discrimination.
3.
the power of making fine distinctions; discriminating judgment: She chose the colors with great discrimination.
So, treating others based on a group, class or category is discriminating. Smokers are a group and a category. Therefore, there is discrimination.
From the Oxford Dictionary:
the unjust or prejudicial treatment of different categories of people or things, especially on the grounds of race, age, or sex
So again, there is a difference between legal discrimination and illegal discrimination.