In the early days of Facebook marketing, many vendors and dealers focused on the number of likes they could get to their page. This was important because those who liked a page were the most likely to see the posts in their news feed. Today, with organic reach pretty close to being dead, likes have take a backseat to reach and engagement.
Facebook is furthering the call for a lowered focus on likes by going directly after them. They are killing off zombie accounts and this is a very good thing. If you see the likes on your page reduced, you know that it's just Facebook's way of dissolving the fakery that's been happening on the site for a while.
As Willis Williams put it on ADM:
The important thing to remember is that Facebook filters out fake profiles better than anyone else. That’s why it’s always been hard for people to “buy likes” for Facebook in recent years. You will lose likes during the purge but it won’t be catastrophic.
Read more on ADM.