[..]
I don't understand the motivation of some of these people - they're supposed to be standing up for the 'oppressed' and fighting 'hate speech' yet this individual was happy to assault a woman with mace
[video]
and of course beat other random people:
[video]
I don't get it, sure Milo is a bit annoying and can be a troll at times but these reactions are just so over the top - he and his supporters/followers really are seen as a threat by the SJW types to the point where they're now reacting violently to try and stop him from even giving a speech.
You don't understand because you're taking the propaganda at face value.
In the USA, the whole idea of liberalism and most of the idea of equality has been infected and corrupted by authoritarian bigots. Their claims to be liberal and egalitarian are lies. Of course the same is happening here, but they haven't been as successful yet.
Where they have more power, such as some USA universities, they feel more free to show their true colours. They're all committed to authoritarianism, which of course includes the suppression of dissent, and to irrational prejudice and discrimination but open violence is only viable when they have enough power. Intimidation and propaganda are more useful tools when they have less power.
Most ideologies of irrational prejudice claim to be about standing up for the oppressed because it's such a politically useful lie.
