RJR is correct. The school class room is not a place of public accommodation. Disabled university students are not protected by the ADA with respect to the classroom and their academic programs. Instead, every university that accepts federal funds (which is nearly all of them) must comply with the Rehabilitation Act of 1973, a law that provides students much the same protection as the ADA and indeed was the law that provided the model for the ADA. There are some differences though.
She is not imposing her values on her students. She is not telling the student he/she cannot smoke outside of class. What the teacher is reacting to is the lingering effect of that action which the student brings into the classroom. When the smoke smell is strong enough to offend others in the classroom then that's a problem for the professor to address. The student has no right to come to class smelling of smoke and so the professor violated no rights of the student by doing what she did. That's really the end of the legal analysis. The Texas case you linked earlier is nowhere near on point. That case involved a student in a public university who alleged that the school interfered with his free speech rights. That's a far different situation since free speech is guaranteed by the federal and Texas constitutions. The federal constitution does not give a right to smell of smoke, and neither does any state constitution, nor any federal or state law for that matter.
I certainly get that you don't like what the professor did, and you are entitled to your opinion that she should not have done it. But as what the professor did did not violate any rights of the OP, there is nothing the OP can pursue in a legal sense on this.