EDIT: Based on your argument, the iconic Marilyn Monroe picture of her skirt blowing up is too mature for public consumption for the sexual undertones it implies.
Clearly I'm not making any progress in explaining things, so I'm gonna leave this because I feel that no matter what I say, we'll end up in disagreement. Intent is important, remember, and you have to ask yourself if there is sufficient intent in that film - because you're not talking about a picture, but a scene from the film The Seven Year Itch, which gives you a whole lot more context to consider - to arouse the audience. I would say that in the film as a whole, there isn't that intent. Certainly not a primary intent, at least. Arguably, there isn't that intent in the scene, either, as "The Girl" in the film does not stand on the grate for a sexual reason (it's because she wants to feel the breeze, and doesn't think it through). And yes, Monroe is credited as "The Girl" in the film, which is primarily about the fantasies of an middle-aged man going through a mid-life crisis, and how he ends up not going through with them to remain faithful to his wife.
Incidentally though, reportedly this scene did contribute to Marilyn Monroe's divorce from her husband at the time, Joe Dimaggio, who stormed off the set in a rage because he felt his his wife being an exhibitionist. So for at least one person, this actually was too mature. Or at least the filming of it - which is certainly a different thing to the story told in the film. And it should be noted that Dimaggio's reaction was kinda extreme.
EDIT: On further reflection, the film "The Seven Year Itch" actually does illustrate my point quite well, insofar that it does have an exploration of the difference between the intent of "The Girl" and the interpretation of the protagonist. It might be worth a proper watch.
