I heard the full story of the woman jailed for two years for a tweet

IANAL, but imminence I believe has to do with speech in a context where people nearby are inflamed and ready to commit violence. E.g., pro-genocide speech in Rwanda in 1994 by people carrying machetes would absolutely count. But a speech calling for violence on the Washington mall in front of a huge crowd wouldn't count unless the speech also included exhortations to said crowd to commit violence immediately. If you went up to a crowd of elementary school children and started exhorting them to kill their teachers that might not count because no one would believe the kids would do it. It's tricky.

The point is that the First Amendment protects speech that calls for violence but without imminence for a reason: if that were not the case then any administration (including state administrations) could punish speech they don't like by exaggerating the speech as calling for violence. By insisting on such a high bar the courts have made it difficult to lower the bar to a point that many might view as tyrannical.