It's more nuanced though. Here's how rich people use charities to gain wealth:

Rich person has tons of money that would be taxed if bill Y passes. Rich person creates a charity and donated 20% of what they would had to pay to the IRS to the charity, with that money the charity uses half for good causes and half is given to X lobby company, which then lobbies politicians to avoid passing that bill.

In the end, the rich person saved 80% of what they would had to pay.

Yeah, 10% went to good causes but imagine what the society could afford if 100% went through instead of 0.

This is a very rough outline of how they do it, but the summary is that they use charities to donate to lobbies while skipping taxes on the donation itself.

Because they are tax avoidance mechanism first and charity seconds.

Money is a brokering system of power, charitues being tax free makes these entities unaccountable to democratic institurions.

That's how we ended up with this infection of corrupt megachurches.

The "prosperity gospel" is billionaire-serving propaganda. It empowers their formation, growth and necessary abuses that come from such widespread exploitation.

The point here is that in many jurisdictions doing charity exempts you from certain taxes, and it is possible to shuffle money around under the disguise of philanthropy while still getting all the financial benefits like an actual charity

Giving away money? You sweet summer child.

Research don't want "his" (the foundations) money, it comes with so many strings attached all your lives work now belongs to the B&M foundation.

https://en.wikipedia.org/wiki/Global_Polio_Eradication_Initiative

Google en passant.