If you want negative opinion, then I am your man. The net value cost of these donations by these philanthropist billionaires should be considered. That is harder to calculate but basically what detrimental impact did generating this wealth cause? Does the donation really offset the damage done? For example, the very pro-business Australian government has been blamed for "shrinking government" by severely cutting back on bush management and firefighters leading to the fires getting out of control. These are the people welcoming the Bezos of the world with open arms. It's money from an ethically questionable source helping solve a problem caused by another group of people making ethically questionable decisions.

Also billionaires combined donate a pittance compared to public institutions likes NIH or NSF, National Endowments and other grant giving orgs funded by the public. Really we should just tax them more and funnel the money to public grants, and also properly enforce antitrust, labor laws and environmental regulations to limit societal damage wealth extraction causes, instead of hoping and praying billionaires will sprinkle a little moolah where it matters every blue moon.