Further it's not "price fluctuation". It's a systemic raising of prices prior to a "sale" event, to deceive people into thinking they paid less than they would have by not waiting for the sale.

As for the person you are talking about may be acting irrationally, but there are many people who rationally wait for something they want to be on sale - because such a thing should save them some money. These people are maybe being naive - but without easy access to perfect market information, they have to rely on some sort of price messaging.

Finally - articles like this are good for people who shop to get better informed. Even if I were to track the price of something, to know that it used to be cheaper, I have no way of knowing if a given "sale" is a good price since future prices are unpredictable. However if I know of the "price inflation before sale" practice, with data to back it up, I can infer a pattern suggesting whether I should wait longer or not on a purchase.