I think real-world examples are very dangerous to provide here, because they can easily derail the conversation into arguing about the validity of those example

I think real-world examples are very dangerous to provide here, because they can easily derail the conversation into arguing about the validity of those examples, because if they are currently unconventional ideas, someone with orthodox privilege will see them as simply false, and bad examples. That's the blindness referred to. The Zeitgeist around the date PG wrote this article is probably no coincidence; if you really want recent examples of divisive topics. Historical examples are great for that reason, and there are plenty in the history of science. One typical example I love, is Wegener's theory of continental drift and how long it was ridiculed, hindering scientific progress, before it was finally accepted many decades later, in the form of the theory of plate tectonics.