Yes and no. Mostly yes, this is marketing, but is not really disguised. It explicitly lists writing such articles as a form of marketing as part of their strategy.
That's right, it's part of the strategy but it's not generating revenue if you think of this from the marketing perspective. If we take into consideration the amount that we made based on the traffic that we got from these articles, it will be around 0.2% of the general revenue in 1 year (~2.000$ of $1M). Me, as the co-founder, I've spent many weeks planning, writing and gathering information to write these articles.