Hey, author of TFA here. Try inverting the color and upping the blue, you might see the patterns. Here's a scan I did from a magazine https://i.imgur.com/x1TXa30.png
It's also possible they are using a different technique. As I mentioned towards the end of the article, the dots have been around for a while and some vendors are apparently looking into other methods
On what grounds do they argue we still need this? I thought money generally has enough safeguards these days that consumer color printers are no longer a threat.
I am not a printer company executive nor an employee of a federal agency (I swear!), so I couldn't tell you precisely the logic behind it. My venture is that while it's true there are lots of physical safeguards to prevent the spread of counterfeits, these dots and other stenographic techniques can be used in investigations to trace the source. If you know what printer was used and what serial it has, you could theoretically track it through the vendor's supply chains.
I also believe that international trade agreements and banking regulations, such as the Japanese measures mentioned in the article, require dots and similar methods even if they have perhaps technically been superseded.
It's also possible they are using a different technique. As I mentioned towards the end of the article, the dots have been around for a while and some vendors are apparently looking into other methods