The vice-chancellor’s talk was a day after a glass pane was smashed during a pro-Palestine protest at the University of Otago clocktower.
A spokesman for Otago Students for Justice in Palestine, who organised the protest this week, said the canning of a lecture about the importance of arts education was an "overreaction".
The spokesman said the group was non-violent and had only ever disrupted talks.
The only concern Mr Robertson could have was "over us asking him the hard questions and his fear of having to answer those".
"We have disrupted Grant Robertson once before at a talk, but all that consisted of was asking questions to Grant about the university’s stance of institutional neutrality."
Mr Hernandez, a former Otago University Students’ Association president, was "deeply concerned by the vice-chancellor’s comments and extremely troubled by the behaviour of Campus Watch".
"Peaceful protest is the cornerstone of democratic society and is something the vice-chancellor himself engaged in during his time in student politics," Mr Hernandez said.
"I was part of yesterday’s protest and it was a peaceful but passionate show of solidarity with our Palestinian whanau.
"Campus Watch’s response to this peaceful protest was completely out of line.
"The university must also respond to the calls of yesterday’s protest and ensure it has no investments linked to Israel and the genocide being committed in Gaza."
Mr Robertson said in a statement it was highly regrettable the incident at the clocktower occurred.
"A number of staff who work in the registry building were visibly upset as a result of what unfolded.
"My job is to protect the safety and wellbeing of students and staff at this university."
Mr Robertson said he stood by his statement that "the protest crossed a line from being a peaceful protest when protesters attempted to enter the building".
"I will continue to fully support the free expression of views and the right to peaceful protest, but also continue to expect that to be undertaken consistently with the safety and wellbeing of those who work in the university."
A university spokeswoman said Mr Robertson’s talk was cancelled by the School of Arts for "security reasons", but declined to comment further.
Otago University faculty of law Prof Andrew Geddis said he was not in a position to comment on the behaviour of Campus Watch staff.
"Campus Watch does have one specific power — under the Code of Student Conduct they can require that a student [but no other person] give their name.
"The protesters have the NZ Bill of Rights Act 1990 rights of freedom of expression, association and peaceful assembly."
Prof Geddis said it was a matter of context.
"The fact that students can usually enter the Registry Building for normal university business doesn’t then mean that there’s a right of free access for the purposes of protest ... It requires weighing up the disturbance caused to normal work by the protest, security concerns, the opportunity for other forms of protest, etc."
