The Death Star's destruction also killed thousands and thousands of soldiers, bureaucrats, and construction workers. A lot of who is good/bad in Star Wars is perspective. The Jedi can also be seen as religious extremists that kidnap children to indoctrinate in their ways, to lead in terrorist missions that help impose their view on an entire galaxy. Darth Vader is an emperor protecting his empire from a growing threat.

The moral is, multiple things can be true.