I guess it depends on how we define culture. Certainly every community, be they a discord server or a twitch chat, has its own micro culture. Memes, references, trends, acronyms or phrases, and symbolism come to mind. I don't doubt that Bezos's power over Amazon over twitch could get some emoji they like banned. But I don't think that's as active a control a culture as I think the article implies. Bezos isn't personally producing a twitch stream the way Broadway producers would. Sundar Pichai doesn't mandate that the casting for a YouTube video isn't what he wants. To say they control culture feels disingenuous to the creators.

Arguably you could say that in the days of the monarchy we only had 1 person, the king, controlling our culture. And I'm sure there's influence. But at least personally I've never heard anyone hold that viewpoint.

"Culture" is misused in this context. It's really mindshare (influence) in the memetic landscape. Actual influencers rather than wannabes. The problem is they're "elected" and respected by a mob or by buying their soapbox, and so they're not particularly educated, wise, or conscientious and bring biases and agendas with them that might not be the most constructive.