Disagree -- you're attacking the wrong cause of your issue. There are many aspects to text being readable than having extreme contrast with colors. As you even said, "white or light background." That already shows malleability. Font style (serif vs sans), line spacing, column width, header:content size ratios, etc matter. You're over simplifying the problem. Making the text #000 won't solve your problems and generally looks worse. When you buy a professional book they also aren't #000 on #fff -- that generally will look bad and amateur.

Design is an art and takes a lot of iteration of all those things I mentioned and more to obtain aesthetics and usability. Personally I find the new DDG hard to scan in part because I'm used to google, but also because there are different elements of the design I think to be poor choices:

1. The black text for header and content doesn't help anything pop. It needn't if everything else is setup correctly, but it isn't doing any favors. Instead the only color between listings is the favicon which makes it feel random.

2. The weighting of the header isn't sufficiently different from the body of the search, giving them less contrast relative to each other, and thus harder for my eyes to scan. If they had put the title in all upper case, chose a bold condense font, bigger font size, etc then there would be more contrast between the two.

3. The listings are variable length with not much white space between them, so that contributes to it being harder for my brain to chunk and reliably scan.

Those are just a few of the issues as I see it. A professional designer / typographer could help a lot more.