I mean, prior to React the big Framework at the time was AngularJS 1 - a hellscape of two way data binding.

Talking about one-way data flows was an excellent way to speak to a lot of tortured souls at the time (who had just found out they were going to be forced to migrate their projects to something else anyway due to Google's absolutely insane "we're deprecating this, we'll have a replacement for it at... some point, good luck").