The President slammed the Supreme Court to its face last night.
Nearly every president finds something to criticize about the Supreme Court, but not every one gets to do it to the justices’ faces, on national television, in the State of the Union speech.Actually, pretty much every President has the chance to do it, since the Supreme Court normally has at least one member present. The fact that it doesn't usually happen has to do with the fact that it's cowardly and unfit to strike someone who cannot strike back.
The opposition party gets to respond formally at the end of the speech, so a certain amount of political grandstanding towards them is fine. (Less fine: calling your opponents liars to their faces, then acting like you're the one who deserves an apology when they give you the lie right back.)
The Supreme Court has no such opportunity to speak directly to the People. They may not, by protocol, even applaud things they like from the President's speech, nor stand to applaud, nor cheer. They are supposed to be outside of politics, and they cannot answer the blow.
It does not help that the President's claim about just what they had done was a... well, it was 'not true.'
The Justices did not deserve to be treated in that way. It was an honorless insult, and a cowardly act.