That would depend on whether the University is classified as a private or public facility, and its charter/rules and regulations of attendance that would govern the actions of its students: what and who the University is legally responsible for on the premises of the University.
Going on the premise that the University is private with rules and regulations governing its students to restrict certain activities as violating its policies that would be penalized by suspension, I would have to concur with the expelling of the students.
Going on the premise that the University is private with rules and regulations governing its students to NOT restrict certain activities as violating its policies that would penalize with suspension, I would have to disagree with the expelling of the students.
Going on the premise that the University is public, and there be any rules or regulations of policy that prohibit such behavior of its students actions on its premises with penalty up to and including expulsion, the University acted accordingly.
Contrarily, if the University is public, and there be no guidelines prohibiting such behavior by its students on University premises as it pertains to policy, the University acted illegally, and may be subject to suit by those expelled.
The American's Constitutional right to "Freedom of Speech" must be protected no matter how that speech is liked or disliked, agreed with or disagreed with as long as it does not purposefully incite a mob/lynch mentality among the hearers that would endanger the lives, or physical well being of innocent persons or property.
Although I am not in support of any form of racial prejudice, or hatred of any sort, the truth, that is truth indeed; as in the case of true religion, being told is often times hurtful to the deceiver, or the one unwittingly involved in the lie, yet the telling of that truth must not be hindered, suppressed, nor prevented by any who may wish to protect the deceiver or the feelings of those effected by the knowledge of that truth. For, how can one make a conscious decision or choice concerning critical aspects of life absent all of the facts for and in opposition to the end result of decisions and choices that would be made?
I hope this answer was helpful to you.
Be blessed, Amen.