And why we don't recommend it.
Here is a little insight into the way Facebook works now - When you post something Facebook gauges how popular it is, decides what newsfeeds to put it in, and in turn gauges how many people and who see your next post. If you post a page share chances are not many people are going to like the post, therefore not many people are going to see your next post which could be much more relevant to them.
While doing page shares can generate new page likes, it is much more valuable to have someone like your page because they saw an item they would like to purchase rather than because someone told them to 'go like this page'. We never mean to offend anyone, we just choose to opt out of sharing all together! The other major factor is that we like to share companies and pages that are reputable. We never want to steer the Barbie Brigade in the wrong direction, or recommend something we don't stand behind 100%!