Frontier hasn't even started discussing what is coming next yet, so at the very least the next expansion is several months away from release. Judging by the fact they only recently went "full production mode" on it, I doubt we'll see any news on it until 2019's Gamescom at the earliest. If that expansion is the first part of Space Legs I wouldn't expect a release before Dec 2019. Then what would be the point in releasing the first hints now, and through some obscure story on galnet of all things? When Frontier does SL, they'll want to hit the community hard and flood the gaming press with all the CGI they can conjure up just a few months before release.
Yes, it's just "fluff to make us thinkg there is more going on than there actually is". People have been enjoying such things, to take their mind off of what actually is, since the dawn of times. If next time you feel like being less periphrastic (and less of a downer), you can call it a story.