I would not go as far and call this a scam, it is a stylized fact of the Google search algorithm. The official Guangzhou airport homepage is horribly slow to load (it took 10 minutes for me to load right now) and no better to navigate as I can tell from past experience. The first hit you mention instead does provide little information and apparently mostly links to the airport hotel, but it is still much better in terms of site performance and thus has made it higher up the Google ranking. There is no use in linking the official homepage first if it does not load for 10 minutes, no matter the officialness or information content.
You should in general try to verify anything that seems dubious on the internet and not blindly trust the first Google hit. This issue might appear more prominent for Chinese internet sites as they are not optimized for Google since Google is blocked in mainland China, they are mostly not in English, and the Google ranking algorithm is not as well-trained by clicks from users and their return rate, etc.
I have encountered similar behaviour in many countries where internet is not so much of a dominant medium yet, including significant differences between European countries.