Gingrich did not say "Trump should probably attend Biden's inauguration."
HEWLITT: “Should President Trump attend the inauguration of President-elect Biden?”
GINGRICH: “Probably. I think that we’ve only had a couple of presidents in history who didn’t. John Quincy Adams didn’t. And the Republicans in 1868 didn’t. But other than those two, it’s a routine. If he does not go, I think he has to explain why. And I’ve written a piece on why I will not give up, in which I’m pretty aggressive about this in general. Not so much the election, but the whole process of where the country is right now, which I think is extraordinarily dangerous. So I think Trump’s got to decide, you know, what best communicates his message. I think his instinct is not to go because he’s convinced the election was stolen."
It was posted this way to get people riled up over clickbait
That’s how I see it too.