More to the point, when people talk about Gates like this, it's both dismissive of his very legitimate philanthropic accomplishments and stifling to any well-reasoned, neutral conversation we could have about Microsoft's legitimate failings.
Let's put aside the silliness of dismissing actual philanthropy by complaining that it puts people in a positive light. If I take the parent commenter's thesis at face value, then Bill Gates' philanthropy is a public relations conspiracy designed to get people to forget "how bad he was" in his Microsoft years. Frankly, I can only hope more CEOs become so publicly vilified for anti-competitive practices that they decide they need to start foundations to spend billions of dollars reducing various life threatening diseases by double digit percentages.
So yes, you could say I'm willing to look the other way, or at least more fondly, when it comes to Bill's Microsoft years. If his public relations strategy is to make himself look good by doing good, then I don't have anything to complain about. What are we supposed to do, nod to each other and say, "Yes, but let's not forget about how evil his company was in the 80s and 90s..." in a somber tone every time his philanthropic works comes up?
It's ridiculous. And most of the vocal proponents of this idea are intellectually insulting, with passive aggressive remarks that accuse people of being shills in a web of lies.
... a bit more than that.
But also not "literally burning puppies and kittens alive in the early days of Microsoft while blasting The Imperial March" ...