Words from the mouths of HR professionals are typically not “legally binding” either, I don’t know where you get that idea, but I recognize it’s a common misconception.
In most U.S. states your employment agreement is on an at-will basis and outside dismissal or discrimination for a set of protected reasons, you’re free to leave employment at any time, and your employer is free to let you go at any time.
Very few verbal interactions create a “binding commitment” for a company. All might be admissible if you brought suit, but “he said; she said; they said” is often more difficult with the passage of time (people are forgetful) and worse than written interactions, and just because you may be allowed to present them as evidence in your claim, that does not make anything a slam dunk legally.
A lot of what you will formally get upon receiving i.e. an offer of employment will be on company headed paper, signed by a person with authority (this is often “Delegated Authority”, that Role can do that Action is written down in Company Policies or a Company Handbook, which itself is reviewed and approved at very senior levels). That’s more “binding” and if you signed and returned, rejected other offers, then it fell through, you might see success in making a claim for losses and injury because you reasonably believed there would be a job and compensation. Even there it is going to say something to the effect of “this is not an employment contract, your status is at-will”, which significantly limits the liabilities of the company in most U.S. states.
So, short of the person you are talking to being a C-level executive or Company Officer, no, most of what you hear verbally isn’t “legally binding”.