Ghost announced today that they are adding fediverse "social web" support to their open source publishing platform and that got me thinking about POSSE again. I've had a draft post sitting around for ages inspired by an article The Verge published that essentially had the thesis: "negativity about cross-posting is a false flag operation to stop people from having their own website."
While that is obviously a hyperbolic expression of a gut-feeling I have little evidence for, I am really glad I had a backup of my long-gone #100DaysOfTrees Twitter thread that I was able to turn into a post on my own website.
So while I can't prove there is a conspiracy to make you think cross-posting is bad, I can confidently say you should have your own website because cross-posting is good, actually.