The core premise seems like it's pushing a human-centric idea really hard only because it actually removes the humanity from it.
Getting hounded every day to try to justify your existence in a company does not sound human-centric to me.
No, because the Agile Manifesto isn't a slogan for a concrete methodology, it is the explanation of a set of values.
The concrete methodologies come from different sources than (and post-date) the Manifesto; the Manifesto wasn't written to sell them.
It's true that there is a mismatch between the values articulated in the Agile Manifesto and the concrete methodologies that bill themselves as “Agile”, but that's not due to the Manifesto being a dishonest sales pitch for the methodologies, it's because the methodologies are dishonestly appropriating the label associated with the Manifesto.
In any case, the people pushing the methodologies overlap very substantially with the people who originally signed the manifesto.
Most “Agile” methods are fine starting points for adapting a methodology to your team needs, which is the only thing a published methodology should be if one takes the values of the Agile Manifesto seriously. But the even where they aren't actively pushed as rigid, one-size fits all, certification and standardization driven monoliths like Scrum, they tend to fail to actually address Agile application...
Agree that the consulting/certification industry makes things worse. Again, that overlaps with the signatories for the original manifesto.