As a gay man raised in a stridently feminist household, it's something I hold very sacred. You can't be the girl who cried wolf, because it makes it harder for everybody else down the line. Including you. You are not holding the line when you bring feminism into situations where it isn't the main thing. You are making it about you, when you do that; you are making yourself the Cheese, and you can't hope to make a rational decision once you've done that. The other side of that, though, is that it's nearly impossible to tell on a case-by-case basis whether it's a valid complaint or not. It's a nuclear option but it's also a constant frontline battle, and telling the difference is a value decision all of us make every day. There may be plenty good reasons to kill individual cops on an individual basis, but nothing like the very good reasons we levy the harshest possible penalties against cop killers. This is the basis of law. And of the kill chain.
Call it the wrong way and you're "being a feminist," barking at shadows that aren't there; call it the right way, and inevitably people on the other side of your understanding -- sexists, Jackie, other feminists -- will say the exact same thing.
So then that becomes the problem. And if you go far enough down that false trail, you get to a place where all feminist-sounding complaints are valid, because if they aren't then none of them are. Suddenly individual choices, thoughts and reasoning don't matter, because you're defending sacred and very much endangered territory. But do it wrong, often enough, collectively or singly, and you invalidate the territory altogether.
Of course there's a feminist side to every thing that goes down: There's an a priori institutionalized gender imbalance that is always present in everything that will ever happen. And it's not enough to say, like the military does, that gender simply doesn't matter: That's just like white people saying color is irrelevant. It's a form of really gross privilege that goes unnoticed and continues to warp our lives because it's so prevalent. We are all fish and we all have to remain aware at all times that "water" isn't the sum total of reality, it's just the way of things for us right now.
But the opposite reading isn't fair either. No easy answer is ever the answer. You throw your lot in with the rule of thumb and you make yourself lazier and stupider. No doesn't always mean no. Bosses aren't always bad for sleeping with their employees. Fall to the rule of thumb, and you're not only lobotomizing yourself but you're also taking away the choice of the victims you pretend to care so much about. An easy answer is comforting, in the moment, and it will always break your heart, in the long term.