It should have started off with Zatanna and Jessica. While launching DCSHG they included Harley & Ivy for name recognition. I guess it was also the first exposure to the characters for a lot of kids. The Lauren Faust version then adopted the DCSHG title but made Harley & Ivy villains which had a whiplash effect for the younger fans and the older fans of the heroic versions became livid.
DCSHG in its original incarnation was a multi-platform revenue generating brand that included toys, comic books and games. It was a huge success that made headlines among trades like
The Hollywood Reporter:
https://www.hollywoodreporter.com/mo...omics-1020570/
https://www.prnewswire.com/news-rele...300410948.html
The CN version was a reimagining of the brand that made some big changes like portray Harley & Ivy as villains when they were heroes during the first wave of the title. This was the introduction to the characters for many kids who thought they were heroes so were left confused as to why they were villains now. It's like if the follow-up to the 80's animated TMNT show had Raphael and Michaelangelo as villains with Casey Jones replacing them on the heroes team.