FWIW, I agree with other commenters that this is a betrayal of trust but I don’t have anything original to add.
I think you’re missing/avoiding the issue that people might want to hide the very fact that they have a Triplebyte account at all. It implies that they have job hunted in the last 5 or so years, and someone who’s been at a single company for longer than that might not want that information to be available.
I work at Google, and I can tell you as a fact that our Privacy Working Groups would never let us launch something like this without explicit user consent.
> Google Buzz publicly disclosed (on the user's Google profile) a list of the names of Gmail contacts that the user has most frequently emailed or chatted with.
Google Buzz is something you definitely don't want to be similar to.