Money and power.
Some people, like 99 44/100% of those of us here on IDW, believe that individuals should be free. However, there are those like Trudeau and the vast majority of of left wing nuts (which is why they are politically left) believe that every person other than themselves should be subjugated to their will. Those who attain police or political power do the subjugation, while the believers without the actual power vote for and promote the people and institutions that do so.
@GaryMysels Sounds like you are saying its pure idealistic Utopianism that is keeping Trudeau in power. Maybe.
But there are a very large number of career politicians seemingly behind him who are as cynical as they come.