I don’t find it that hard to believe, they’re responding anonymously so they know it won’t hurt their specific company’s image, and the general message of “there’s a lot of untrustworthy bullshit out there for job seekers (so if we do make an offer you better take it because your fallback plan might be a mirage) (and, y’know what, just in general - we have all the power here and we are going to lie to you and not feel bad about it because thats normal for us, so don’t even think about complaining to anyone about it)” is one that serves all their interests
I think your “On the other hand etc.” is a pretty accurate guess at specifically how they do this, tho