It's not coincidence, and it's not conspiracy. It's zeitgeist, and people seeing one place do something and decide that's a good idea, and people following everything from scientific (and pseudoscientific) studies that came out around the time, to philosophical works published around the time, to all of the above that were old but re-popularized around the time.
You can just as easily ask "why was there a rise of right-wing nationalist and fascist sentiment throughout the Western world in the mid-to-late 2010s?" There's no grand conspiracy to any of it, and looking for one is likely to lead you down exactly the road that far too many conspiracy theorists have gone recently.
And, um, closely related, be aware that the "lizard people rule the world" thing isn't just a funny joke. It's deeply and inextricably rooted in a raft of antisemitic tropes, slurs, and propaganda going back...I forget exactly how long, but at least many decades. In fact, in general, when you encounter any conspiracy theory that posits a shadowy group of people secretly ruling the world, the chances are nearly 100% that you can trace it back to a version where that "shadowy group" is explicitly Jews. This is a big part of why conspiracy theorists have a tendency to find themselves in a pipeline to fascism.