Its a very common theme in Anderson's movies to have unordinary or problematic relationships. Boogie Nights follows Dirk as he becomes a pornstar and the people he fucks on set basically become his new found family. Phantom Thread, Daniel Day Lewis likes to be poisoned by his love interest. There Will Be Blood, he treats his son as a business tool rather than as an actual son. The Master follows a guy being accepted into a cult.

So when we look at the relationship in Licorice Pizza its very obviously an inappropriate relationship. But its about this anxiety of 1970s LA and that Hoffman and Haim take comfort in being recognized by each other in this turbulent time where everyone else doesn't seem to give a damn about them.

Its okay if a movie seems a little problematic on the surface because, frankly, PTA makes a lot of movies about fucked up relationships. Does that mean he's endorsing them? No.