Don't get me wrong, Namejs. Only a very small number of people in Germany have the chances to play hockey and even less on a regular basis or can start as young kids. But that doesn't mean hockey is not popular in Germany as a
spectator sport. Actually DEL is the second most popular sports league in the country with more than 2 mio spectators / year in the stadiums.
As all other non-football leagues though in Germany only a certain percentage of the population follows DEL or hockey (actually a big part of hockey fans prefers NHL over DEL). So in regions like Cologne, Düsseldorf, Bavaria, Saxony or Berlin you have good chances that people will know teams, players, results etc, in Hamburg, Saarbrücken or Frankfurt rather not.
PS: A lot depends on coverage in media. The derbies between Cologne, Düsseldorf, Krefeld are covered a lot in big regional newspapers and so it's the case with Eisbären Berlin - who even get a lot of attention by national press. Also newspapers in Bayern have a lot of coverage and local tv stations show highlights of games. Definately not the case in Hamburg...