So, the Beyonce fever becomes pitched in large part because of algorithms suggesting that content. I don't think each of those tweets would have happened independently.
The critique is that we're being fed so many suggestions that we don't have room to find out for ourselves what we like or want to talk about. Instead many times we're simply responding to and consuming the recommended content.
So there are people at the wheel, but the majority is along for the ride.
Japanese people are individuals, but Japanese society favors the collective, and the person who goes along to get along. Accordingly, people are rewarded for adding their voices to the throngs supporting something that is already popular or favored by the elite, much less so for cultivating individual tastes, which are pushed to the sidelines (think back-alley Akihabara with its tsundere maid cafés and other businesses of peculiar interest).
In the USA we put high value on "being an individual like everyone else". Social media has simply amplified the "like everyone else" bit by making it easy to keep track of what everyone else is doing. Something that's been ongoing in Japan for decades if not centuries. (The koseki can be considered a form of paper-and-ink social media.)
That's not diversity, it's simply pop culture.