Why would putting up content here that people like to read not be promotional to Hive? I haven't been on Hive that long but in the time that I have been here I am glad to follow users here that can put up something worth reading. That is why the author is frequently gaining upvotes and rewards.
This in itself is promoting Hive because if people are spending time reading these posts as apposed to some other social media platform then that is drawing traffic to Hive. Promotion doesn't have to be an advertisement which are for the most part ignored anyway.
It's not completely worthless but in my opinion not deserving of this much rewards, if they even attempted at driving traffic and onboarding their followers to hive so they would engage with their posts more and learn the benefits of hive curation on posts and comments, feeless donation txs, etc I may even join in and reward such activity.
Other than that if they fail to even garner much attention from users here then they should be fine with a little lower rewards until they do better, same goes for most "influencrs" or what you want to call them who have a following outside ans only thing they do is crosspost or leave a comment here and there.
You would think that driving more traffic to Hive would be beneficial to the author's own self interest which would lead to more rewards so there is some point to what you are saying and I think the author will likely take note of this.
Try not to go negative though. Compared to a lot of other content you could find many other posts to take issue with before this.
I do look at other posts too so it's not like I have a personal issue with this one or it being about the content.