These redefinitions probably grew out of "critical theory" which is taught in social studies. The initial protests citing this line of argument seem to have started on college campuses, so there might be some merit to saying it grew out of academia.
Well, when people are arguing over the meaning of words - in this case "racism" - it is sometimes useful to reference what the "experts" think. There are entire fields of study within academia dedicated to this topic (often but not always including the word "critical").
Of course, whether or not said people have anything meaningful to say on the topic is not broadly agreed upon.
