I don’t think anyone can answer this to your satisfaction without knowing your personal definition of journalism. Because I believe the question you’re really asking is, “Was 538 what I consider journalism?”

When I typed “define journalism” into Google, this came back:

> the activity or profession of writing for newspapers, magazines, or news websites or preparing news to be broadcast.

So yes, 538 was journalism by at least one definition of journalism.

Here’s one more definition:

> Journalism is the activity of gathering, assessing, creating, and presenting news and information. It is also the product of these activities

Another yes! We’re 2 for 2!

> Was 538 journalism?

Yes, it was, and still "is" until they take the website down: https://fivethirtyeight.com/

All fact-based reporting on politics and current events is journalism. I'm sure some of your HN comments have been journalism.

538 is a bunch of opinionated statistics and bad editorial. Squarely in the center of journalism.