Maybe the Dingoes Ate Your Toad

This story about toad-licking dogs in Australia is amusing and may even be true, but it raises a question: Don't cane toads secrete their psychoactive toxin to discourage predators? Or rather, doesn't this trait persist because it makes toads that have it less prone to being eaten and therefore more likely to have lots of offspring? If predators actually enjoy the toxin, what's the point (evolutionarily speaking)? Does the toxin only repel predators native to Australia (so dingoes don't like it, but Irish setters do)? Or are the toads so much fun to have around that predators avoid eating them?

Update: It turns out the cane toads are not native to Australia either.