They do this every few months or year whenever licenses change and sites that do links like this pick up new books. Comickey, Azuki, J-Novel Club, K Manga, Viz, whatever.
It's usually independent of the DMCA takedowns and nothing ends up coming of it because most of them will, at best, post the first few chapters, then maybe post the first chapter of every volume, then give up on the series in 3 months because it didn't attract the readership they wanted or whatever. Part of the reason I've never been able to get into using some of those sites, even the ones that offer free simulpub chapters, is that they tend to quit before they've even caught up to where the fan scanlations were.
I don't doubt that eventually a day of reckoning for Mangadex will come where they no longer allow pirated scanlations, but this is not anything any different than has happened before and there's no reason to believe that it's a harbinger of immediate change.
