"No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, ..."
And
"... nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."
Let's see how SCOTUS tries to get around these
The author of this is really twisting the story in his own favor. He leaves out the part where he launched public personal attacks against other faculty and students.
His department did try to work with him so that he could teach his class (which was completely outside his field of expertise, and is therefore against the general policies). They wanted him to co-teach with someone with knowledge in the field, but at that point he had completely ostricisized himself and no one wanted to work with him.
This is absolutely a situation where someone fucked around with a loaded gun, shot themselves in the foot and is now mad at everyone else because they didn't help him shoot someone else.