I mean, a single sophon could have eliminated humanity by itself using a fraction of the power presented as being possible in the books, in hundreds of differen

I mean, a single sophon could have eliminated humanity by itself using a fraction of the power presented as being possible in the books, in hundreds of different ways. But I do think it's worth suspending disbelief a bit to try and enjoy the other ideas presented. It's fiction for entertainment, not a serious warning to stop broadcasting signals out into the universe.