OK: The “MAGAbomber” label sure seems to fit Cesar Sayoc Jr., who was arrested Friday in the mail-bomb packages sent to leading Democrats.

But the case still stands as a warning to political and media figures across the spectrum that it’s long past time to put an end to incendiary rhetoric.

That’s certainly on President Trump & Co., but also his host of critics.

Sayoc drove a van covered in Trump stickers; his Twitter account was filled with antipathy to liberals and conspiracy theories. But his record of instability goes back decades: He pleaded guilty to making a bomb threat against his local utility company back in 2002.

Such anger-driven, unstable people are absolutely vulnerable to being inflamed by angry rhetoric and extreme language — to the point of taking extreme action.

We’ve seen it before: In 2017, a Bernie Sanders fan whose social-media posts railed against Trump and Republicans as traitors opened fire on a group of GOP congressmen, nearly killing House Majority Whip Steve Scalise.

However high partisan passions rise, the extreme rhetoric has to stop. Shame on Trump for applauding a candidate who’d assaulted a journalist, and shame on ex-Attorney General Eric Holder for calling on Democrats to “kick Republicans when they’re down.”

A bipartisan return to civility and respect is imperative — and neither side should wait for the other to make the first move.