Sure. Dating back from the days of radio and cassettes, it is (to my knowledge) absolutely legal to make copies of streams for private use. Since artists are payed for copies via the GEMA, a organization distributing the german hidden taxes for it, people have the right to make such copies.

Copies for private use are as such not a gray area, but explicitly legal. I fail to see how a site that helps making those copies could be illegal in any way. There was a court fight in Germany over the backups the site was doing, but it is telling that it was only about that, not the core functionality, and that this current attack on peoples right was launched from an US court.