"Are you claiming that utilitarian ethics are wrong?"

"Right" and "wrong" are usually concepts that are applied with respect to an ethical system. Which ethical system am I expected to assume when trying to make sense of this questiion?

"Are you claiming that most charities are actually fraudulent and don't help people?"

No - I was not talking about that.

"Isn't exploiting people for their own ends incompatable with being utilitarian?"

If a charity's goals include "famine relief", then considerable means would be justified by that - within a utilitarian framework.

"Charity pyramids" was a loosely-chosen term. There may be some pyramid structure - but the image I wanted to convey was of a cause with leader(s) preaching the virtues of utilitarianism - being supported in their role by a "base" of "suckers" - individuals who are being duped into giving many of their resources to the cause.

Superficially, the situation represents a bit of a Darwinian puzzle: Are the "suckers" being manipulated? Have they been hypnotised? Do they benefit in some way by the affiliation? Are they fooled into treating the cause as part of their extended family? Are they simply broken? Do they aspire to displace the leader? Have their brains been hijacked by pathogenic memes? What is going on?