The entire thing was horrible and profoundly unethical. His brother has stated it really changed Kaczynski.
Some people have claimed that it was run by the CIA as part of MKUltra. This is certainly possible but not really substantiated by clear evidence as far as I've seen, and even if the CIA has some relationship they probably didn't instigate the experiments but just asked for research notes or something relatively benign like that. We'll probably never know for sure though.
Whatever the case may be, of the group of students that were subjected to these abusive experiments only one became a terrorist, so "the CIA created the Unabomber" is rather simplistic IMO. The primary blame remains with Kaczynski, no matter what.
Source? What is the incidence of terrorism in that group and in the general population?
Also: many people (myself included) were extensively and viciously bullied in their childhood and/or teen years. Many suffer profoundly negative effects from this, sometimes for decades or even their entire lives, but most are not terrorists. And even if it did turn out that the incidence of terrorists was higher: that still doesn't absolve them or their own responsibility in committing violent acts against random people (i.e. terrorism).
[1] https://exploringyourmind.com/the-harvard-experiment-that-le...
"A Freedom of Information Act document released by the Central Intelligence Agency in 2018 states that "a considerable amount of credible circumstantial evidence suggests that Theodore Kaczynski. also known as the Unabomber, participated in CIA-sponsored MK-ULTRA experiments conducted at Harvard University from the fall of 1959 through the spring of 1962".[26] Chase and others have also suggested that this experience may have motivated Kaczynski's criminal activities"