It’s probably organic. It often happens that the HN front page coalesces briefly on a theme. People see an article on a topic, research it a bit, and post what they find (or just repost something they remember from last week). And similarly it gets more upvotes on the “new” page because interest in the topic is active.
This is called Baader-Meinhof Phenomenon [0][1]. Every time that you buy a new car, you see the same one everywhere you look: "hey! I just read one article about Tesla, here's 3 more!" when there is usually several articles each day about Tesla.
There are a surprising number of Apple and Tesla posts lately. While I am not yet convinced it is being outright paid for, but there does seem to be a higher concentration of specific brand advocacy here than there used to be. I wonder if it has to do with so many people also being share holders with a vested interest in their success?
I’ve made a similar observation before. Most “negative” Tesla posts disappear quickly, even though they seemingly have enough votes and comments to stay up. Probably flagged to death.
Comments wrt Tesla/Musk-related stories are also much less diverse and more rage-laden in content. Sentences are also more likely to start with The Brand Name than otherwise, as it'd be worded in universe in The Truman Show. It's just weird.