How or why Scott Adams went completely of the rails is perhaps something we'll sadly never understand. Was this opinions he'd always had, but suppressed, did he somehow become radicalized or was it perhaps medically induced, e.g. a stroke or something. It was incredibly sad to see him throw away his life's work and go down a path most of us at least hadn't foreseen and die having alienated his fans.
It started at roughly the time of his divorce, so it's hard to imagine there's not a connection. But, of course, you're right that we'll never know.
I don't want to excuse his opinions but that's the sort of event that can change a person.
He did online chats, and did one immediately after. It's a tough watch. https://x.com/ScottAdamsSays/status/1046764270128484352