Facebook is punishing calls for likes & shares.
'Engagement bait' is the term Facebook uses to point out such content, referring to 'clickbait'. Posts like 'Respond if you are born in May' or 'Tag your friends if their names are in this picture' are seen as engagement bait. Shortly: every call for interaction - or engagement - which is not really founded on meaningful content will be seen as engagement bait.
Facebook wants to ban this content from everyone's timeline and uses Machine Learning to make it happen. Pages that post engagement bait repeatedly risk a low appreciation within the algorithm of Facebook. That's something you want to avoid because the algorithm determines to how many people a post is shown.
Facebook says not all posts or pages that encourage liking or sharing will notice the hunt for fake engagement: the algorithm should recognize posts about fundraising for charity, missing children or other posts that really do require interaction.