You don't need to decide up front for every possible statement whether it's true or not. You don't need to decide up front for every possible statement whether it's hate speech or not. When you come across a proposition, it's your responsibility to decide whether it's true or not. You have to be open to the possibility that you can make mistakes, even really bad ones. That's part of the responsibility.

Likewise it is an abdication of responsibility to just pretend like speech can't be destructive. It's your responsibility and the responsibility of your community to deliberate on what sort of speech is destructive to the purposes of that community. And you have to admit that you can make a mistake and deal with it. That's part of the responsibility.

Free speech absolutism is obviously on its face a dogshit principle because it is unlimited and thought-ending. Yes, the suppression of speech can cause harm, but this harm is not infinite and permanent. Any principle that does not allow thought, deliberation, and thus necessarily the ability to make a mistake and the ability to make up for mistakes is a stupid principle.

The harm of suppressing speech without good justification must be measured and balanced against the harm of allowing harmful speech. The existence of harmful speech is hardly debatable: If speech wasn't powerful then we wouldn't consider free speech important. If speech is powerful, then its power can cause damage and harm. Deal with it.