Hmmm. Maybe I'm not best-qualified to comment on this, given my free use of "sexual swear words," particularly the dreaded "C-word," which, to hear some people talk, is objectively offensive, and renders the utterer beneath consideration.
'Sexist' thinking still present in writing
However... If, as the researchers claim, the use of language in this way is historical and the male/female ordering of salutations and names dates to a time when men were valued more highly than women, is it true that men and women are still viewed in this way, solely because the male/female order has been retained, habitually? Put another way, if I don't know the name of the person to whom I'm writing, then I'll write "Dear Sir or Madam," not because I believe that "Madam" is less valuable than "Sir," but because that is the way I was taught to present a letter, when I learnt to type. And the RSA standard of presentation does not inculcate through some kind of pervasive, subliminal indoctrination process any kind of hierarchy in my mind, viz-a-viz the relative value of the genders, notwithstanding the historical model.
Now, I know that I shouldn't generalize for my own case, and there may be people out there who have allowed themselves to perceive the world in accordance with the language that they've been obliged to adopt, and maybe the research carried out suggests this to be the case. And maybe it doesn't.
...Not enough information. Actually, do you know what? I've lost interest...