I had similar feelings before I left Facebook. This sort of thing even irked me back in high school, but I couldn't quite put my finger on why.
Every time it was my birthday, my timeline (or "wall" as I think it's known on FB) was inundated with Birthday wishes and greetings. Most of these greetings and wishes came from people who very rarely, if ever, talked to me on FB and oftentimes, never talked to me in real life (Usually my "true" friends would send me a direct message and wish me a Happy Birthday), and these people most certainly wouldn't know when my birthday was if Facebook hadn't reminded them.
It all just seemed so disingenuous, fake, and at the risk of exaggerating, inhuman. It all felt so joyless and disconnected. Before I left FB, I simply got to the point where I wouldn't comment, like, or interact with these birthday wishes in any way. Eventually, the amount of birthday wishes I received became less and less. Thinking about it now, I probably should've just removed my birthday from Facebook.
Regardless, I'm happier without Facebook and I certainly don't miss it.
I figured out that Facebook itself is not awful. It may be in many ways, but it is my 'friends' who drove me away. When I was around them they seemed semi normal. But put them behind a keyboard and the truth came out of what they were and how they really thought about me and my beliefs. Their inner keyboard warrior came out. They were not real friends but 'friends' of proximity. I had confused friendly with friends.