As Friedrich Hayek explained in The Road to Serfdom:

Advancement within a totalitarian group or party depends largely on a willingness to do immoral things. The principle that the end justifies the means, which in individualist ethics is regarded as the denial of all morals, in collectivist ethics becomes necessarily the supreme rule.
And make no mistake about it, the social justice crowd is about gaining power so that their rules apply to everyone.

I guess the egging could have been a coincidence and have nothing to do with Peterson's anti-social justice positions but it sure has the feel of an SJW action. They don't want to debate, they want to intimidate.

But good luck trying to intimidate Jordon Peterson.