Unpacking the whole context and philosophical debate (e.g. between libertarians and Marxists) requires a book-length argument. (But to briefly answer your question, no. “People ought to be entitled to what they create” is not a universally accepted principle.) So folks responding to Graham are mostly not going to do the topic justice.
(Side note: In a similar but less defensible way, Paul Graham’s summary of Joseph Stiglitz’s several books about inequality [to wit: “The most common mistake people make about economic inequality is to treat it as a single phenomenon. The most naive version of which is the one based on the pie fallacy: that the rich get rich by taking money from the poor.”] was such a ridiculous oversimplification that I suspect either (a) Graham didn’t actually read any of Stiglitz’s books, or (b) he has extremely poor reading comprehension, or (c) his argument is not only self-serving but also entirely disingenuous.)
But anyway, you can’t just strip out all the context and pretend Paul Graham is having a purely abstract argument in a vacuum. The context today is that the level of inequality and centralization of political influence in America is at a level unseen since the 1920s, or perhaps since the gilded age. There’s a political discussion going on in the society at large about whether this development is healthy, and if not, what to do about it. Many people are angry, to the point that Paul Graham’s essay itself is full of paranoid fantasies about being “hunted”.
Anyone making an argument in modern America is implicitly talking about what direction we should be going from where we are currently, and what social/political changes we can make to get there. Most readers are going to understand such arguments with that context in mind, and only bad/lazy writers will ignore it.
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Graham grew up in a well off family, went to Ivy League college and grad school, worked for a few years as a programmer for his own well-timed web startup then cashed out for tens of millions while he was a relatively young man and transitioned into venture capital, where he has been very successful. As far as I can tell he has basically never worked in any jobs other than being a student, running his own startup, or venture capital. He apparently surrounds himself with other rich techies and has no regular exposure to people outside a tiny cultural bubble. From what I can remember, his only essays which talk at all about folks less fortunate than himself are about his school experience, in particular what I can remember is whining about how English teachers are idiots and how the jocks mistreated him.
From such a position of privilege and ignorance, Graham hand-waves away all the concerns of the vast majority of people in America (not to mention the world), and spends his time justifying his own wealth and prestige and insisting that he shouldn’t have to contribute any of it back to society, with the bulk of the argument being “startups are good”, without further elaboration or analysis.
As you might imagine, this seems awfully cheesy to folks reading along who don’t happen to be multimillionaires themselves.