Less AIBU than trying to establish what the norm is, I suppose.
When Facebook tells me that it is [insert random aquaintance]'s birthday, then unless it is a close enough friend that I think "oh shit I didn't send a card", I tend to ignore it. Does this make me grumpy and antisocial?
FWIW, I haven't added my own birthday to my profile, and my profile is locked down quite tight, so I don't expect/need/want anyone to be wishing me a Happy Birthday either..