Yeah, I don't know. A few of those guys aren't exactly huge disappointments, considering they went outside of the Top 10. Someone like Kriss Dunn wouldn't be a huge disappointment if he had been drafted around 13. And most of them were just inept picks by clueless FO's. The problem wasn't their age - it was just really stupid management. Look at Epke Udoh getting picked at #6 FFS - but then notice that it was Golden State, back when they were totally mismanaged. That list leaves off Luke Jackson who went somewhere around 9-10... but that was Cleveland who didn't do much of anything right, other than have LeBron fall into their laps. Araujo was the result of that belief you talked about that any 7-footer who could walk and chew gum could be an NBA player - but it was also the perennial doormat Toronto that picked him.
I think Brandon Roy was 22 when he was drafted (if not, he was within a month or so). Caron Butler was 22, and I don't think he was a big disappointment. I'm pretty sure Danny Granger was 22 when he was drafted, even though he isn't on the list either (sorry, Granger fell just out of the lottery. ZWJ). David Lee was a 4 year college guy, so I'm pretty sure he was 22. Jameer Nelson was old when he was drafted. David West, Josh Howard - I'm sure there are more. The problem isn't the age. It's that when you have a solid lottery pick, you really want a guy who stood out so much in college that he just had to leave early, because the expectation is that there are stars available in the first 6-7 picks. After that, it's the same choice the Spurs are facing - swing for the "upside" fence and try to back-door a future star, or pick a guy who's likely to be in the league for 8+ years, and who might become a second-tier star through grit and effort. I know West was gassed by the time he got here, but if you told me that the Spurs could draft a young David West at 11, I'd jump on it, even though West was almost 23 when he was drafted.
The biggest red flag on Toppin, IMO, is that he doesn't defend or rebound for , and he likes to play above the rim. To me that says he's more interested in highlight reels than a winning team. But if Golden State was picking 11 instead of 2, I guarantee you they would scoop him up. There's nothing Kevon Looney can do that Toppin can't already do much better. Back in the day, I would be confident that the Spurs could get him to defend, but now I'm not so sure.
Edit: Whoever made that list above cherry-picked to make a point - just because of Roy, of no one else. By the time you get out of the Top 10 (Top 7, really), you can't afford to overlook 22 year-olds who are obviously NBA ready.