Can you really discuss whether there should or should not be free speech at Princeton (or any other university) before you discuss what the purpose of this institution is? Is the institution there to enforce a certain common set of beliefs and attitudes, some of which are labeled acceptable, some desirable, some doubtful, and some racist? Or is the purpose of the institution to encourage research, thought, and service to some community, local, national, or whatever? The slogan "Princeton in the Nation's Service," what does it mean? I think too many speak their mind without knowing what they hope to accomplish and whether what they hope to accomplish is desirable or not, accepted by the venue or not, etc. Jean-Jacques Rousseau distinguished between the Will of All and the General Will. Scholars differ on exactly what he meant, but at least he meant, I would venture to say, that what people want (or want to say) is not the same thing as what they should want (or want to say). To some this could sound totalitarian; it has to many scholars. To others it recalls that good societies need citizens (or Republics need republicans) who are less fixated on their desire for rights and more devoted to their civic duties -- duties to the whole community. A different understanding of freedom underlies these distinctions. So since freedom of speech is a RIGHT, should we perhaps think about whether it should be supreme or should be secondary to the Duty to tell the truth.
I have never made up my mind about all this -- still as a professional academic of the 18th-century mind -- but I offer my observations in the hope that more fundamental things will be discussed and pondered, rather than whether Professor X should have been shouted down by Messrs. Y and Z.