I saw this, on article online..It says otherwise.
Information you share publicly: When you choose to share something with Public (ex: when you select Public from the audience selector), it’s considered public information. If you share something and you don’t see an audience selector or another privacy setting, that information is also public. Learn more about using the audience selector to control who you share with when you post to Facebook.
Stuff other people share: If other people share info about you, even if it’s something you shared with them but did not make public, they can choose to make it public. Also when you comment on other people’s public posts, your comment is public as well.
Posts on Facebook Pages or public groups: Facebook Pages and public groups are public spaces. Anyone who can see the Page or group can see your post or comment. Generally, when you post or comment on a Page or to a public group, a story can be published in News Feed as well as other places on or off Facebook.