I don't need to cull anything because I never allowed Facebook or myself to build such a fake list of friends and relationship to begin with. However, even with only close family in your list, FB (or any other service besides the email service you trust) is not worth sharing anything that is of private nature. Ultimately, FB is as same as any other place on the internet.

I use FB's private nature of service for close family and friends only to email them as it is convenient.