I think Trump was being cheeky/sarcastic in his statement, just like he's always been with the press. And why the mother-loving F is he still newsworthy? He's not president anymore, thank the stars--just a blowhard has-been who couldn't get elected for a second term.
But that's unfortunate about Nigeria banning Twitter, as it's a slap in the face to freedom of expression. Not that I particularly care for their platform, but I don't think they ought to be banned in any country unless they're doing something wrong, which I don't believe they are. Hopefully that doesn't become a trend in Africa or elsewhere.
REAGEN is still a think in politics, think about how ancient that is, most of us weren't even alive back in those days, First president in my time was papa bush, then Clinton when I was a kid, then bush jr when it was a teenager and Obama during my college and afterwards, and most recently trump when I started to bald a bit and losing hair. So we only had such a few presidents in the past 30 years, it is normal that people are still news worthy, Obama still becomes news time to time when he says something, hell "who will the previous president personally nominate as his best candidate for next president" is still a thing, and that is really a big deal.
This is not a big news, it is just Trump and Twitter feud because it gets clicks and that's it, but I still think whenever an ex president does something it is a news because people read about it.