When you see [flagged] on a submission, it means that users flagged it (this is in the FAQ: https://news.ycombinator.com/newsfaq.html). We can only guess why users flag things, but in this case it's pretty easy to guess - just read the first part of the site guidelines: https://news.ycombinator.com/newsguidelines.html.

There are plenty of current events sites out there. If such stories weren't mostly treated as off topic here, HN would be entirely a current-events site. Yes, there are exceptions—you can find detailed descriptions of how we approach that in these past explanations: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so.... But I don't think this submission would make a good exception. It's a political horse race story. I realize that in this case the horse race turned out to be historic, but that's not going to make for a thoughtful, substantive thread (perhaps 20 years from now). As evidence for that, I give you: this actual thread.