How can protozoa (that’s a plural word, not that today’s journalists care about grammar) be resistant to chlorine? It must be bad luck that so many sanitation-related diseases are appearing at the same time as we are dealing with large numbers of illegal invaders from the third world.
Same way brewer’s yeast is resistant to alcohol, some microscopic beings are tougher than others. And crypto has been around a long time, first recorded over 100 years ago, they’ve just now decided it might be a source of funding so there’s a big kerfuffle.