I would think if you personally provided them your information, and their TOS stated that this info, once verified would be added to their publicly available database for all to view, I don’t see how they could be held liable. This lawsuit will most likely be judged on that TOS.

Amazon: Actress lawsuit over age revelation bogus
Her failure to identify herself in the complaint without first seeking the court’s permission violated court rules, they said, and although they believe they know who she is, they’re not entirely sure. Furthermore, they argued, when customers subscribe to IMDb Pro, they agree to a privacy policy which makes clear that the database can keep and use certain personal information.

“Even if IMDb.com used plaintiff’s name, address or zip code from her credit card subscription to locate her birthdate, such use is consistent with the subscriber agreement and privacy policy,” they wrote.

She argued that she never consented to having the personal information she provided used for anything but the commercial transaction. IMDb refused to remove the reference to the woman’s age from her profile when asked, the lawsuit said.

IMDb agreed that it had refused to remove her birthdate and noted in asking the judge to dismiss the case that the actress had also requested that the company falsify her age on the website.

On the matter of:
what if it was a case of a adult film star known by a stage name but their real name was not publicly known? If imdb published his or her real name/ d.o.b. and that allowed a stalker to locate/ injure them, would imdb be liable?

Unless they had some kind of court order against a stalker or were under the Witness Protection Program, I’m not sure if there is any law protecting against release or a re-release of such info once it has been made public.

This actor has been trying (and finally got) IMDb to put his correct age on their profile of him:
An Actor Pens An Open Letter To IMDB; Says He’s 4 1/2 Years Younger Than They Claim

Dear IMDb: Actors have a tendency toward narcissism, so I try not to Google myself too often. Of course, occasionally I need reassurance that there is, in fact, a body of work attached to my name.

But reassurance is not what I get when I click on my name at IMDb, the industry’s bible for factual information about movies, television shows and the people who make them. Yes, my credits are listed (more or less correctly) on the site. But IMDb informs me that Robert Lesser is a 73-year-old gentleman who was born in Los Angeles on May 28, 1938.

I understand your policy is an attempt to stymie impostors who might seek to prolong their time as “leading men.” I admit I would like to linger in that category for as long as possible. I’ve even been putting money aside for a little nip and tuck down the road. But I don’t want to be rushed.

It is difficult for me ? as it would be for a court of law ? to calculate the impact that your “willful disregard” for my correct age has had on my career. However, if you would consider changing my profile to lop just 10 years off my actual age, I could be persuaded not to sue to recover damages for all those leading-man parts lost and the mountain of earnings and royalties I would have made.

and:
Or if they more simply lost the actor in question lost their ‘real world’ job. Are those consequences something that can be contractually signed away?

As an example, losing ‘real world’ jobs is something that happens to porn stars all the time when their stage name is connected to their real name. If your job has a ‘morals clause’, or your new found fame is causing a disruption at the workplace and costing your employer money, expect to be out of a job soon.

Google:

“stage name” porn star lost job

to see plenty of examples. The only one held liable is the actor in question.

Then Google:

“stage name” porn star lost job sue

to see how many file lawsuits over it.

Anyone can sue for anything. This Canadian guy takes the cake:
Male porn star sues government for $100M