Only joking, but no it is not "projection". It is definition. It goes something like "people do what they want to so if they donate something to others it is because they wanted to do it and therefore it was not selfless."
It's a pretty stupid and pointless definition though, probably sprung from someone's need to economicsify human nature. Even then you can easily get around it by defining selflessness to be the selfish need to give to others.
https://www.psychologytoday.com/us/blog/imperfect-spirituali...
I see reasoning like this online all the time. A person donates $10 billion, and people say they it must have given them a warm fuzzy feeling, and that feeling is by definition worth $10 billion, because that's what they paid for it. As if the idea of selflessness or human goodness or anything existing outside the real of rational economic exchange is so challenging they find it more plausible that a warm feeling is worth $10 billion.
(Not that I think MrBeast is particularly an example of altruism - although it's probably an example of good)
Having behaviours that benefit your group rewarded and reinforced seems an obvious survival trait. It feels good, like reproduction. I wonder it's purely societal evolution or if there's a genetic component there.
Maybe it's hard to reconcile all this because calling something altruism is subjective, since we are not all knowing.
Like those act of kindness videos on YouTube with millions of views and earning the creators thousands of dollars.
This may be some kind of projection or just your personal opinion of society and human motivation. You aren't inside the brains of every human and can't possibly know everyone's motivations at all times. It's quite possible that some or many of them experience authentic altruism.