One of my hobbies is creating recipes. I may start with a recipe or just an idea - and then work, and work, experiment, have failures and successes, until I come up with a perfect (for me) recipe.
If someone asks me for one of those, I won't share. I will share any recipe that I have used from a magazine, internet or cookbook. My own creations are only shared with my DDs.
Why should it be expected to share? Should a designer share their patterns? An author his writings? An artist their artwork? Cooking is an art, developing recipes is not easy, time consuming and expensive.
Heck no I'm not sharing unless "I" want to share.