I think it's pretty short-sighted if you can not envision how hearing particular views can be a starting point to harm.
Let's take a view that is different to mine and probably yours - it is what many people would call a racist viewpoint. It's held by an individual who has done a lot of research and feels that they have found evidence that a certain ethnicity is inherently more likely to be less intelligent and also inherently more criminal. They think they have stats and research that can back this up and that the social factors that others think may be at work are not actually relevant at all. They think they have found 'The Truth'. They think they are entitled to share this information, as it is 'The Truth' after all. They demand platforms to raise awareness of their views and have proposals to mitigate the harm that others may experience from this group's increased inherent criminality. So should universities then give this person a platform to share their viewpoint? What is the harm? It's just another viewpoint, right?
The potential harm is that others believe this rhetoric, develop a corresponding cognitive bias or perception error and come to think of this particular group, and all individuals that are in it, as more likely to be inherently criminal. They act differently around them, they avoid them, they treat them differently, they feel suspicion and hostility because they have been persuaded by this viewpoint. The people who belong to this group also hear this viewpoint and internalise these attributions and begin to think differently of themselves - they are told to think they are inherently more criminal, less intelligent; they experience shame, and low self-esteem.
The two factors together combine to create a powerful sentiment against, and negative outcomes for, this group. The spreading of this viewpoint encourages other to feel prejudiced and hostile towards them, and has fuelled self-loathing for the individual. They lose confidence to participate in society or to seek support. They don't know which environments will accept them or where they will be shunned. They achieve less educationally and in the workplace and their health and wellbeing outcomes are lower and their lifespan is many years less that the average. The stigma, hostility and lack of social support that they face makes them more likely to become involved with the criminal justice system...
...and this is the icing on the cake for that first individual who wanted to promote their viewpoint - because now they feel they have even more evidence for this supposed increased inherent criminality that they were talking about.
But it's just a viewpoint right? How on earth could that be harmful?