**Although moderate amounts of the flesh of the apple is perfectly safe for your dog to eat, you must use caution when giving this treat to your dog since the covering of the seeds contains minute amounts of amygdalin, a compound that contains cyanide. Theres some evidence that suggests the stems may also contain traces of cyanide, so its best to remove them, too. To be harmful, the seed coating has to be broken in order to release the amygdalin, so if your dog consumes a few seeds whole, he should be fine. **
https://www.vetinfo.com/is-it-safe-for-dogs-to-eat-apples.html
That said it is true some of my vet's have been militant about stuff other vet's say is no problem.
What's it say about grapes? Pupster loves ‘em but poisonous or not?