This is basically what people wishing happy birthday on Facebook has become, along with the customary expressions of thanks. Automated to be able to do it for all your 3000 “friends”.
I have a friend who passed away many years ago. We are still Facebook friends. Many of her Facebook friends still wish her happy birthday every year. I just cannot think how sad that must be for the husband.
I've removed my birthday from Facebook for this reason. I know people have the best of intentions but I really do not want to reply to a bunch of messages wishing me well. It is just plain awkward and an unpleasant activity.
I can never understand the FB “friend” bugbear. It’s just a name for a relation. It has no implied connection to how people relate elsewhere. Calling it “acquaintance” would be more accurate if you really insist on such a connection. But that isn’t exactly catchy: “I sent you an acquaint request on FB”; “let me just post this question to my FB acquaintances”