"Ad hominem" means "against the person." An example of what that might look like in your scenario: someone makes an argument for free speech and in response someone says "but you're a Canadian and everyone know Canadians aren't to be trusted, therefore free speech is bad!" An ad hominem happens when the speaker is attacked instead of the idea the speaker has presented.

In your case, pointing out that there are social costs to free speech is perfectly legitimate. We could explore that idea a…