This argument attacks a criminally strawmanned version of the case in support of no-platforming. No-platforming does not typically happen to people that unions find merely annoying or silly.
The reason speakers get deplatformed is because they make marginalised people feel literally unsafe existing as themselves, or because they espouse ideas that directly harm marginalised people.
The students who support no-platforming are capable of dealing with challenging, complex arguments. When they no-platform a speaker they have simply made an evaluation that the ideas they espouse are either directly dangerous to the student body, or not worth engaging with.
Just because the world is a dangerous and violent place towards marginalised identities, this doesn’t mean that universities should replicate that environment within their walls. If they can make life better for LGBT, ethnic minority and disabled students within the university, why shouldn’t they?