Using 'bastardize' often implies disapproval of the changes made to something pure or good. The chef felt the new recipe bastardized the traditional dish.
Pro Tip 2/3
Lesser Quality
Emphasizes the decline in quality due to the addition of inferior elements. The unauthorized sequel bastardized the original film's legacy.
Pro Tip 3/3
Preservation Efforts
Often used in contexts where there is an effort to maintain the purity or integrity of something. The museum's policy ensures that no artwork is bastardized by restoration attempts.