But is this really a problem? LinkedIn is "advertising for yourself", presumably to get a job. With the exception of my phone number, I'm ok with the world knowing this information about me. It's the equivalent of a phone book and I'm putting myself out there and advertising myself in the hopes of getting a job.
Well I can see your point, but this is not exactly the same. As a thought experiment imagine that someone now builds a website called Linkedout and they post your profile with a layover animation resembling a big red stamp which reads 'Slacker'. I guess you are not OK with THAT information about you.
Isn't that what someone that works at Slack? If they're getting basic employment details that badly wrong, then they're not very useful.