Nessum, I dont think there is any rational way to evaluate your hypothesis. The problem with sexism (or any other ism), as noted before, is that you cannot evaluate the action, but you must evaluate the MOTIVE.
When we are on a boat charter, and I pick up your tank when I walk by, am I sexist? Maybe.....you dont know.
If I offer to help you with your gear, or let you know that you have a hose trapped behind your BC, am I sexist? You dont know.
If PADI uses he to represent the diver in their literature, are they being sexist, or conforming to language norms? Again, you don't know.
Unless you know WHY something happens, you can't evaluate if the actions is sexist (discounting the most obvious examples, which, happily, have almost disappeared over the past decades).
Unless you know me, you cannot reasonably predict my motives, and wont know if Im sexist. I'll tell you though, if I do you a favor, and you accuse me of being sexist for it, you may end up going for an unexpected dip. Many people get extremely upset for being wrongly accused of something, especially when their intentions were pure.
The problem with movements like feminism is that you will find sexism if you want to. To some women, if I go through a "manhole" cover to get to the sewers, I am sexist.
I am not saying sexism does not exist, only that argueing about it is pointless. A circular arguement is like a merry-go-round....its kinda fun, but you dont get anywhere.
Just a thought
Wetvet