What about "Let's give all the Russians wet willies?"

There’s no clear line on free speech so we could do endless hypotheticals, but the line has never been at 0% or 100% of all possible speech.

https://en.m.wikipedia.org/wiki/United_States_free_speech_ex...

> Categories of speech that are given lesser or no protection by the First Amendment (and therefore may be restricted) include obscenity, fraud, child pornography, speech integral to illegal conduct, speech that incites imminent lawless action, speech that violates intellectual property law, true threats, and commercial speech such as advertising.

Your hypothetical isn’t included in any of the current exemptions to free speech protection.

The US legal standard is imminent lawless action, not just any lawless action. I doubt that some a HN/facebook commenter is going to cause hoardes of people into pour into russia and do illegal action, so that hypothetical is probably legal under US law.