Billionaire philanthropy is as old as robber barons, and has long been a tool of washing the blood off of the legacy of the immensely wealthy.

Cornelius Vanderbilt, often considered the first of the robber barons, built his fortune first with steamboats, using his money borrowed from his parents and vicious business tactics. He later became one of the wealthiest people ever by building a monopoly within the nascent US railroad industry link. He pioneered many of the tactics used by the wealthy to abuse the rest of society for their benefit. A notable instance is the 1877 railroad strike, which occurred in response to him cutting the wages of his rail workers by 20%. As should be utterly unsurprising, he blamed the economy being depressed and encouraged the workers to work harder to improve business. link The strikers were naturally faced by police, militia, and national guard opposition. Around 100 people were killed as a result.

Vanderbilt was not one for philanthropy, but later on life did make some donations to churches (at his wives' behest), as well as to what is now Vanderbilt university. It's not an accident that he is remembered as the most reviled of the robber barons, to us now, and during his day.

Andrew Carnegie really was the one who established the trend of the incredibly wealthy giving away money as a method to launder his abuses of his workers and smaller competitors. Carnegie wrote an essay "The Gospel of Wealth" which outlined his belief that it is the duty of the immensely wealthy to give their money away, famously writing "The man who dies thus rich dies disgraced" link

However, when we focus on the libraries and schools Carnegie built, we lose sight of the abuses he committed. Andrew Carnegie built his steel empire by savagely undercutting his compittion. He achieved these prices by cutting wages aggressively, crushing unions and forcing workers to work long hours in incredibly unsafe conditions. The Homestead Strike occurred in 1892 in responses to back to back wage cuts. Violence broke out between steel workers and the private strike breaking firm, the Pinkertons, whom Carnegie hired. Seven workers and three Pinkertons were killed. Naturally, the National Guard was called in by Carnegie's underling Frick to finish the job. link

Two years later, in 1894, McClure's magazine published a piece by Hamlin Garland, which is fascinating and worth a read link. To quote Hamlin's guide:

"Yes, the men call this the death-trap... they wipe a man out here every little while... (death comes) all kinds of ways. Sometimes a chain breaks, and a ladle tips over, and the iron explodes--like that... Sometimes the slag falls on the workmen from that roadway up there. Of course, if everything is working all smooth and a man watches out, why, all right ! But you take it after they've been on duty twelve hours without sleep, and running like hell, everybody tired and loggy, and it's a different story".

Bezos, Gates, Buffet, and their ilk very much follow in this same tradition. They spend their lives abusing workers, and destroying the lives of rivals to amass unimaginable wealth, and use philanthropy in their later years to wash the dried blood off of their image. No amount of philanthropy justifies their actions. No human makes that amount of wealth without viciously abusing others.