To me this seems like a semi-obvious minmaxing solution to making popular videos: make essentially zero profit, regardless of revenue. At some point you get so much revenue that you can't spend it all so the next logical step is to simply give it away as part of the video. And in this case it's a virtuous cycle - apparently giving away money generates more revenue so it just keeps going. But this doesn't strike me as being done out of any noble purpose - all he wants is YT view and charity is just a side-effect of that.
"How can you watch the video where he pays for the blindness surgery for all those people and say that that was anything other than an amazing win for all those nice people?"
My criticism would be that it's local change vs trying for structural change. Why don't those people already have access to surgery? The counter-argument to this would be that structural change is somewhere between very hard and impossible, so just spend the money locally. A more cynical take is that lobbying for restructuring the US health care system doesn't generate YT revenue, so he's incentivized to fund the most clickbaity charity projects.