They were breaking an ancient law, rebelling against Eru, sacrificing humans to Morgoth, slaving lesser men of Middle Earth and encouraging elvish racism.
You say that, but it was not everybody on Númenor who took part in those atrocities and crimes. Many innocent Númenorean lives. Not that I dislike the outcome, flawed gods are fun.
And what about the Numenoreans who were just going about their lives? The ones who weren’t among the faithful, but weren’t taking an active role in persecuting them? What about the babies? Was everyone who the Valar murdered on Numenor responsible for these supposed crimes? And did any of those crimes warrant death?