"So basically everything I used to be able to get in a phone book."
Assuming you had phone books from every city/region in every country. Thats a lot of phone books so you must have had a large warehouse to store them all. Then there is the fact that phone books did not list number for every individual. Multiple persons routinely shared the same number.
The comparison sounds apt in theory but in practice it isn't. Try looking these Facebook users up in the phone books of their respective locales, via the telcos' online phone books or directory assistance. Then, using what you find, tell me their email address, gender and Facebook user ID.
Good luck.
The problem with this argument, "all email addresses are public", which I see regularly on HN, is that information does not become "public" and lose its "private" designation if it is published without consent or lawful purpose. If someone steals secrets and publishes them, they are still secrets.
Whether this information from Facebook is truly "private" I cannot say but I do think it is possible to have email addresses that are not made public.
The recent NSO iMessage story was interesting because the exploit seemed to rely on NSO getting lists of mobile phone numbers for the targets. Not email addresses. Yet iMessage will work without a phone number, with no SIM inserted. Perhaps the targets chose to use phone numbers for iMessage, not email addresses.
Consider what happens if someone creates a Gmail address but never uses it to send mail, and never shares the address with anyone, except Facebook. If this person does not make their Facebook profile public, how is this address public information. Google does not publish a list of every Gmail address. According to the logic of the parent comment, they might just as well. Email addresses are "public", right. Because some HN commenters think they are.
What happened when someone scraped Apple's servers to obtain the email addresses of Apple iPad users. Did federal prosecutors think the information was "public" or "private". The media called the incident "theft of e-mail addresses".^1
1. http://www.nbcnews.com/id/41196595