The explanation is that that kind of post doesn't provide as much "engagement" (i.e. likes, shares and in the end ad revenue) as the kind of posts that makes fa

The explanation is that that kind of post doesn't provide as much "engagement" (i.e. likes, shares and in the end ad revenue) as the kind of posts that makes facebook a worse place (click-bait kind of articles, "fake news", gif memes etc). Something like this happened to me too (though it was about a newborn baby). FB simply decided that some of my contacts are not worth showing up in my feed. Some other instead keep popping up, despite me clicking "Hide post - See fewer posts like this" like mad.