It's my opinion that this topic has become a 'thing' as a replacement for previous anti-feminist topics as denigrating a women because her breasts aren't big enough, she's not wearing sufficiently sexual clothing, she's too assertive, etc.
Decent people understand that deriding a woman's sex and behavior characteristics is bad. So, now we innocently observe, "I'm not saying you 'are' a bitch or bad person, I'm making a technical observation."
But, I think it's more of the same. People (including other women) can't stop themselves from interpreting women relative to their own desire. Nobody feels compelled to take a stern expression on a man's face personally. But, if it's a woman, people feel like she should change to make them more comfortable. "Smile, honey."
Well fuck that. I hereby declare war on the whole idea of 'resting bitch face'. It is anti-feminist and denigrating. Women have faces of all sorts. If they aren't talking to you, what they are thinking is none of your business.
Fortunately, this NY Times article mostly says this...
"We don’t inherently judge the moodiness of a male face. But as women, we are almost expected to put on a smile. So if we don’t, it’s deemed ‘bitchy.’ "