And the story is even more complicated than that. Savvy Star Wars fans are well aware that before Disney acquired Lucasfilm, there was a unique multi-tier canon system in place for Star Wars. Top tier canon were just the Original and Prequel movie trilogies (and, later, The Clone Wars animated TV series). That was it. Nothing was allowed to clash with top tier canon and everything beneath that, such as comics and novels was allowed to exist only insofar as it stayed clear of the true canon.

Lucasfilm would firmly deny this, of course, except for when it actually happened and then no one commented on it. Although Lucasfilm was careful to prevent any major inconsistencies and thus decanonizations, this happened when The Clone Wars came to fill some gaps in the Prequel era and inevitably clashed with Karen Traviss' popular Republic Commando book series. She was asked to revise (or retcon, as it is usually called) her novels to fit with the new additions to the canon and when she refused, the entire series was swiftly decanonized, end of story.

Lucasfilm kept silent on this as well as several of Lucas' interviews over the years where he clearly stated that the EU was a separate universe to his own (not at all unlike the "Prime" Star Trek timeline) because it protected novel and comic sales. Fans would gobble that stuff up regardless of actual quality (some of it was quite good, other works were terrible) and this was a side business that kept Lucasfilm going in-between Star Wars and Indiana Jones productions. These fans took the EU very seriously and invested in it, not because of the actual quality of the storytelling, but because it enlarged the Star Wars gospel and universe.