Using double spaces after every sentence is not new; in fact, people have conflicting opinions on how many spaces to use after the period. The simple answer is one space, but many people disagree with this. It is not a question of who is right but why only one space is the correct thing to do.
The biggest argument is the readability of the article. While this was true when the primary source for typed documents was the typewriter, it is not true now. Typewriters used monospaced type, which means that every character uses the same amount of space regardless if it is an “I” or a “T.” Because of this, sentences looked messy and uneven; using double spaces made each sentence flow into each other much better.
This is not the case now, so the readability argument is no longer valid — if it ever was a good case. However, if using a monospace font, the sentences are still going to look loose and uneven. Most people use double spaces because this is how they were taught, but reading any typography book now is going to teach you better. Continue learning and improving those articles!