I mean, there is a difference between criticizing an idea - or a person - and being purposefully insulting about it. Surely there is a way to draw a line in between that preserves free and civilized discourse.
I fully agree. I think we should start jailing all the people who called Trump an idiot or a racist. That's no way to talk about the President!
I must be able to say whatever I want, and you must be able to ignore me or openly disagree.
No sane government will prevent you from generally moving around. But try to run around the town naked, and see how long it'll take before you get in trouble. Being naked is a form of expression too - one that's almost universally frowned upon when not confined to private spaces in presence of adults only.
(Also, no reasonable government is tone-policing discourse in general. Some governments choose to demand respectful behavior towards the institution of government, including in particular towards officials while holding office. That's a far cry from being oppressive or constraining the marketplace of ideas.)