I’m sure you’re a comic genius. But even a genius can have an off day. I submitted my joke to a peer-reviewed board of professional humorists, and it killed!
That analogy doesn’t describe the OP’s situation either. He said that the people who he can assume would have read his announcement didn’t respond. Not just anyone who is on his friends list on Facebook.
To address the rest of your post, I view it differently. I look at it this way:
I (generic I) have people on my Facebook friends list. I post on Facebook a major event in my life (e.g. the birth of my baby). Those people have several posts around the time I make my post, talking about trivial stuff.
The possibilities I see are:
a) The person saw it, but didn’t feel the need to say anything to me.
b) The person uses Facebook a lot, but the way they use Facebook means that they don’t see my updates.
In case a): they are not much of a friend. Your etiquette seems to be “I don’t have to congratulate you on something unless you send me a personalized announcement”. I think that is being childish. If I found out through my friend’s blog or Facebook posting “I just had a baby”, I’m not going to ignore it and think “well obviously he didn’t care to send me a card announcing it so I don’t have to respond until he does.” I’ll say to myself “Maybe, as a new father, he’s busy, and doesn’t have time to send out announcement cards?” To him I’ll say “Congratulations! How’s it going? What’s the baby’s name?” etc. I can take the two minutes to type up an e-mail, or, even more shocking, actually respond to him on Facebook!
in case b) - They’re not reading my updates, so there’s no reason that they should see them.
Doesn’t seem that complicated to me.
If I unfriend someone (or remove them from my updates list - the two are essentially the same for me, because that’s what I use Facebook for - to communicate with people via status updates etc.), and they notice, they can easily ask me what went wrong, or ask to be my friend again. If they don’t notice, then again, it’s obviously no big deal. If they decide to sit there in a snit, never mention it to me, and stew about it, then, what’s the expression? They are “displaying all the maturity of a petulant child.”
I can see your point of view, and I don’t say you’re necessarily wrong. But I can see the OP’s point of view also, and I don’t agree that his position is totally unreasonable.