Free speech doesn't mean you get to keep your job when you say it. It means it isn't illegal or impossible to speak your opinion. That doesn't mean being as ass has no consequences.

I disagree but even leaving that comment aside, the OP is saying you aren't allowed to talk about it openly. "Allowed" does not imply a government here, but society/employers/etc. If your employer fires you for saying "fuck", clearly you aren't allowed to say "fuck" at work.