I responded in the comments as follows:
"Definitely a tough situation.
But consider this, does he also have a tendency to use words like that for his younger male collaborators or students? Like "Kid, kiddo, buddy, son, etc?"
I don't think "dear" is marginalizing, sexist, or any of that. Is it gender specific? Yeah, if a male is saying it, because he would probably never call a male student "dear" for fear of getting labeled as gay. But what if it was a female collaborator or mentor who said it? Would you be offended then? Or would you believe it to be a term of affection?
We really have to be careful with this shit. If you make assumptions about his intentions based on his gender, then you're just as sexist as you imagine him to be. Period. Now, if you make the assumption based on his personality - not sexist. That's why I ask you to consider how you would feel if a woman said it to you. If the answer is the same, then consider speaking up and respond as you would to a woman who used the term.
Also, if you bristle at every pet name someone in academia throws at you, I have to imagine it's going to be a very long, hard road for you. Sometimes a pet name is just a pet name. I call my friends "sweetie" all the time, regardless of gender, and it is never meant to marginalize them. My husband gets pissed when I call him "kid" just like you would have every right to go apeshit if someone calls you "Little Miss." THAT would be offensive no matter WHO said it."
The parts I've highlighted in bold are what I really want to focus on here.
I understand that in my head I live in this imaginary world where everything is fair and everyone knows the social psychological reasons behind everything and uses that information to make life better for everyone. I get it, but bear with me.
Intention matters, folks. It's the difference between a Murder conviction and Manslaughter. (Well, there's more to it than that, but again bear with me.)
If a female mentor calls you "dear" or "sweetie" - do you have an immediate problem with that? If not, why not? If she starts calling you "sexy" or "little miss" then we have a whole different sort of problem.
We can't run around assuming that men are being sexist when they use terms like "dear" to refer to a female. "Dear" is in and of itself neutral. We begin letters with it all the time, regardless of the gender of the recipient. The name that follows it depends on the perceived nature of our relationship with that person.
When we assume intention using gender as our only evidence, we are being sexist. Making assumptions about anyone based on a group of which they are a member, whether it's men, women, a racial or ethnic group, an age group, etc. is the very definition of stereotyping.
Some men are sexist. And if a particular man is sexist, a larger pattern will emerge where he consistently belittles and patronizes women he comes in contact with. We can then label him as a sexist.
WE MUST PRACTICE WHAT WE PREACH.
You may recall that I recently met with a self-proclaimed feminist department head regarding my possible enrollment in her graduate program. She assumed that, because of my dedication to my marriage and concern for my husband's prospects regarding the move, that I am not committed to my education and career.
But if I was a male student who was meeting with her who was concerned about my wife's prospects and expressed dedication to my marriage, would she have made the same assumption? Probably not. In fact, she might have done whatever she could to help me figure it out, thinking how nice it was for a guy to be so concerned about his wife rather than putting her second to his career.
That's not equality. That's not feminism. She made an assumption based on my gender. And it pissed me off.
I am willing to bet that if the post-doc who wrote the letter to Dr. Isis called out the collaborator on his use of the term "dear" - he would be shocked. If she is truly uncomfortable with it and would be regardless of the gender of the person using the term, she should say something. And if a future female collaborator uses the term, she should say something then, too.