Translation:In comparison to that apple, this apple is more delicious.
Agreed. There is some arcane rule for when to use "with" or "to" with compare but most people don't know it or ignore it. I think "with" might actually be preferred here because apples are similar and literally comparable. In "Shall I compare thee to a summer's day?" the comparison is metaphorical.
OT sort of: Doing this lesson now reminds me of taste test I was given last night by the wife of the professor I live with in Saigon. She gave me a bowl of six orange slices and asked which ones tasted better. I said the three slices farthest from me was more delicious, they were noticeably sweeter. They were grown in the south. If you do not like really sweet oranges, pick the ones from the north.