338k people suddenly registering in one day is news.
As a journalist, the logical question when writing that article would be "why did so many people register suddenly?" And so you write that part into the article/headline to add context for the reader who will probably have that same question.
Otherwise people say "what a shit article, why is this on the front page of Lemmy? I can look up that number for myself"
I've had a similar thought about it. The timing of him dropping out was near perfect in hindsight, right after the Republicans locked Trump and Vance in and taking all of the wind out of their sails right when they were eyeing the finish line. If someone planned that far in advance they'll definitely deserve to gloat!