I think they're talking about people who go to the feeds and click on the clap button without every opening the post or profile.

I open a feed, for example, poetry or fiction, and scroll through looking for new folks to follow. On those feeds, for reasons I cannot fathom, Medium includes a clap icon. You could just go down the line and clap everything in the feed. In fact, as I scroll, there've been times I accidentally hit that clap. When that happens, though, I make sure to open the title and genuinely read it, rather than just undoing it.

I open every profile that interests me in the feed and check out their titles, often reading one or more before deciding to follow. If I open a title to check out their writing, and I'm not interested or put off by something in it, I will still give them the 30 seconds or more and one clap, and I'll highlight something (because earnings calculates the first highlight too). I don't typically leave a comment on those posts. I might, however, leave an editorial note in private messaging if I feel like their writing might benefit.