Paul Allen didn't come from any kind of privilege. So is the theory that he should be robbed of his amazing success and effort also, by association with Gates' association with his father and his father's association with Gates' grandfather? He did go to the same school as Gates after all.
If you want to put it in numerical terms: going from 100M to 100B is arguably easier than going from -10K to +100M (even though there is less money involved)
He is not suggesting his privilege wrote Gates software for him, but that privilege gave Gates a substantial advantage over the large number of other people writing software and starting software companies at the same time.
His privilege is unlikely to have been a sufficient condition to explain his success, but it is also entirely unrealistic to assume that his privileged background did not provide him with a number of benefits, down to even basic stuff like growing up in an environment where success and ambition is expected and normal.
If the civilization into which Bill Gates sold software were 1/10th the size, it would have generated 1/10th the value with almost the identical amount of work on his part. There's an enormous lift given to fortunes just by the fact that they are built in the context of a civilization which is large enough to support them.
None of that is to say that either specific inherited status or personal hard work aren't huge contributors to success as well, but it takes an enormous amount of work and attention to make sure that a large, well-functioning civilization remains large and well-functioning, and that's an oft-neglected factor in how big these large fortunes become.
I worked with someone who failed businesses over and over, each time going back to live off his family's wealth for a bit until trying the next businesses, until finally one of them hit and made tons of money. If you ask him, he'll tell you he didn't inherit a cent, and was a self-made millionaire. Technically accurate, but doesn't tell the full story.
It's been a nice little success. It might be the most successful independently owned donut shop in the area.
But we all know that her donut shop, despite the significant amount of cash necessary to purchase the building and jumpstart the business, is just a hobby for her, the same way sewing quilts is a hobby to my mom. My mom doesn't fret about the few hundred bucks she may put into her quilts, even if she doesn't make a dime off of them. And the billionaire's wife won't fret if the hundreds of thousands of dollars necessary to even test the business all go to waste because nobody buys their donuts. They will barely notice the money has been spent. If my mom wanted to just start up a donut shop here for fun, well, that would be absolutely impossible--it wouldn't even be an option.
Why do I bring any of this up? Because context matters. Bill Gates is self-made, yes, but you have to interpret "self-made" in context. His little jumpstart, which appears minor in the shadow of Microsoft, constituted more success than most people in America will ever enjoy over the course of their lifetimes.
While that's somewhat true, the fact remains that almost all of the people on that list might not be there if they weren't born into at least the upper middle class. They took advantage of the privileges given to them, so it's not like they don't deserve it. But there are likely those from poverty and the lower middle class who work their ass off setting up businesses in things they have access to, mainly restaurants/stores, and only ever move into the upper middle class as hard as they try and as gifted/intelligent as they may be.
[1]and perhaps others like Zuckerberg more so than Buffet, who could probably have somewhat more slowly honed his investment skills and found patrons whilst working the sort of day job people with ordinary middle class backgrounds can easily get.
What was the unique opportunity of that kid some streets down here that got gunned down when he was 10 years old?
What was the unique opportunity of the record amount of slaves worldwide? (by the way, did you knew the world has more "traditional" slaves now than any other time in history?)
Or... what is my unique opportunity? Being in debt? Not having a single important connection? Going to shitty university? Yes, I am intelligent, I make games, but I see lots of people with less skill than me earning millions, just because they were friends of someone somewhere or their dad was the minister of something in the government. Ultimate example: Eike Batista, that CLEARLY is incompetent, since none of the business he started on his own had profits, yet his father that was the mining minister obviously had a hand in Eike 90% accuracy in finding minerals in areas previously surveyed by the goverment during his father tenure while this information is "secret" and private companies should not know, and the government recently happily handed him billions and kicked out thousands of people from their homes so he could make his lastest failure project.
Sure, as did you when compared with 99% of the worlds' population.