I don't think dogs dislike cats any more than cats don't like dogs. It's just that for hundreds of thousands of years they have lived as animals that hunt each other. Dogs come from wolves and cats come from wild cats that were domesticated and breed to be what we have today (more tame and cute version), but their brains still have the same hunter wiring, so a dog/wolf thinks of a cat as a meal, and the same for a cat. Any predatory animals put together would act strange with each other. I think it is more they don't want to be around each other and get eaten, even if there is no chance it would really happen, but their brain still thinks that way.