There was only one time during this film when I felt the presence of a male gaze--when Juliet and Pauline were frolicking in the yard around Ilum (Juliet's home) and they stripped off their clothing, eventually sharing a brief kiss. It was at once tender and innocent and excitingly queer, and innocent in that tired school girl way. However, I do not believe this detracted from the film's standing as queer.
Yes, I believe queer directors/actors have an added level of experience to bring to their films and perhaps this makes for a more nuanced portrayal of queerness (or in Waters' case, a more, um, unique and never before seen portrayal of queerness). But this film was based on a true story, with the voiceovers being lifted directly from the diary of a young queer girl (despite what she may have said decades later). I thought it received excellent, non-sensationalist and non-exploitative treatment from Jackson. You do not need to be queer to deftly tell a queer story.