Investors are humans, like all the other humans, who happen to have the ability to commit significant funds to things, including startups, cars, and charities. There is a well- known challenge of putting large charitable donations effectively to work; that's why Warren Buffett put all his money into the Gates foundation rather than starting The Warren Buffett Foundation or donating it to the Red Cross.
Seen through that lens, it's straightforward to see how enabling people to come up with innovative and effective new charities that startup investors can help fund is a worthwhile project.