https://www.agilealliance.org/agile101/12-principles-behind-...
It would be odd if "business people" just meant the developers' upper management within their firm; supervising costs and parking spaces; but not those without a stake in using the software that results, say.
In fact the only time the customer is mentioned is in principle one: “Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.”
Business people absolutely should be involved - product owners & stakeholders (or a proxy for them).
That’s fundamental but again: business people != customers.
You seem to think stakeholders/product owners are devs direct managers too. That’s rarely the case, if ever, on any functioning agile team I’ve seen. They’re orthogonal to each other.
I don't believe I can be of further assistance to you.
You were never any “assistance”. You had nothing of substance to add.
The point is that there are always stakeholders and product owners - it just makes that explicit. If the PO is acting as a proxy for the stakeholder (customer in this case) that's ok.
Of course the PO might be wrong... but with small iterations that should be found out quickly and adjusted for.