Now I confirm that it is an error of whoever wrote it, thanks for the clarifications, and sorry about my English
Beware of the articles especially when their topic is about cryptocurrencies. They may bring confusion. I don't fault them, though; learning about Bitcoin or any other cryptocurrency at a technical level isn't easy. It is required from you to ask questions whenever you feel you have to.
For Bitcoin, study from reliable sources such as bitcoin.it, bitcoin.stackexchange.com, learnmeabitcoin.com. I personally consider this forum great if you're newbie and thirsty to learn.