How do we know that opponents of MWI aren't succumbing to antibrunoist prejudice?

> [Giordano Bruno] is known for his cosmological theories, which conceptually extended the then-novel Copernican model. He proposed that the stars were distant suns surrounded by their own planets, and he raised the possibility that these planets might foster life of their own, a philosophical position known as cosmic pluralism.

I need to point out that he was burned at the stake for advocating cosmic pluralism.