Yeah I don't think any reasonable person believes this is the absolute inviolable sacrosanct ideal, nor is this actually a legal standard anywhere.

Spouting falsehoods under a false pretense as an authority shouldn't be protected. Otherwise what's stopping society from drowning in a he-said she-said of conspiracy noise?

A reasonable person might reason as follows:

1. If the government is to restrict speech, then it must be granted the power to restrict speech

2. If the government is granted the power to restrict speech, then it may misuse this power in its own perceived interests

3. If the government misuses its power in this way then democracy will be threatened

4. Democracy is good

Conclusion: the government should not be allowed to restrict speech

That means blackmail, threats of violence, divulging state secrects, forging documents, fake passports, and terrorist propaganda should all be allowed.

Agreed.