Which, again, is why DDG says "official site" with an icon next the the official site for something. You can lead a user to an official site, but you can't make them click...
Who the heck cares about some "official site" indicator? That's almost as useful as a SSL security indicator. Which is to say, it's pretty damn useless for the average person. Anyone savvy enough to know what the SSL indicator means or to know to look for some official site indicator probably doesn't need those in the first place.
The first search result is almost always the official one because the search results themselves have pretty high integrity. Do a search for Flash on DDG. The first three search results all point to adobe.com. But what do you see
in front of those search results on DDG? Hey look, it's a scummy site that delivers Flash with bundled adware! There's no prominent indication that the ad result is shady ("Adobe Flash Player Free" doesn't exactly scream "scam", now does it?). Yes, there's a little indicator there that says "Ad", but sometimes ads can actually be official (e.g., search for "Microsoft", and the ad that appears is for the local physical Microsoft Store in my town). And obviously, people do click on that ad for Flash because if it's not profitable for the scammer, why would they keep paying for it? Sure, you and I would never click on it. But you and I are not most people, now are we? I'm sure you've supported less savvy users like family members. Can you imagine them clicking on that link? I certainly can.
The more important point is this: if the search results for Flash already deliver people to the correct official site, then what's the point of an ad? The
only legitimate site for Flash is at adobe.com, but why on earth would Adobe take out an ad for Flash when they are already the top search result? The people who take out ads for Flash are the people who otherwise would not appear anywhere near the top of the results and who are trying to siphon away some of the less savvy users. And the users who miss the little "Ad" indicator and miss the fine print on the scammer's site disclosing the adware almost certainly aren't looking for some official-site indicator.
Anyway, when it comes to this particular issue, DDG is no better than Google. Actually, Bing is better than both of them for these three test searches (flash, firefox, irs) as the ad results don't appear before / above the legitimate search results (though Bing does put ads first for other less prominent searches).