you know, it's interesting, your initial post asks people a simple question: do you need to put a handmade dress that you hate on your daughter just to make your mother-in-law happy. and most people agree that the common decency answer is yes. and in fact from the way you worded your initial post, you do sound pretty petulant.
then, instead of taking the advice that you asked for, and applying it to your situation, and trying to find a solution (after all, you asked; it's not like these folks were stopping you on the street to offer random criticisms), you decide that you're being attacked and you unleash on these people, adding details that are certainly relevant and no one else could have known, and blaming folks for using the info you provided to offer advice, and blaming them for not using info that you didn't actually provide.
it sounds like you already had your answer inside and you weren't really looking for advice, you were looking for validation. what you asked for was advice, and then you were angry because that's what you got when what you wanted was validation. ask for what you want, or don't get mad when you get what you asked for.
sooooooo..... we get back to what I think is a much more fundamental issue. you see the world through your lens, and you certainly do not seem very willing to give others the benefit of the doubt. I have this idea that, despite the fact that, on paper, your MIL does sound at the very least complicated, maybe we're still not getting the whole story. maybe you're contributing to the vitriol that exists between the two of you. maybe you're forgetting that it's possible for a woman to feel shut out from her son's life once he marries (you know the old saying, "a daughter's a daughter for the rest of your life, but a son's only a son 'til he takes a wife."), maybe you're not having much empathy for her, and she's not having much for you, and someone has to drop her dukes and actually try and communicate. maybe she doesn't ~want~ to be controlled by her DIL and she thinks that as an adult and a mother and your senior, she doesn't have to subject herself to your dictates. just because you have ideas about how your children dress and behave doesn't mean they're the only valid ideas out there; maybe dropping your defenses a little and letting her in will open you to a whole world of ideas that you never considered. after all, she raised the man you loved and respected enough to marry and have children with; isn't that good for something? doesn't that at least gain her entry into some kind of inner circle with you?
maybe not. I'm actually not defending her, though I think you will have to drop your defenses against me, which I am quite certain are up, and actually read what I am saying with an open mind and an open heart in order to see that. and I'm not sure you're there yet.
but consider if you can: in all these difficult, complicated, inflamed relationships (with advice-givers, MIL, husband....) there is only one common denominator, and that's you. so maybe you need to look in the mirror for some of your answers.
good luck. I hope you find the strength of heart to open up to the many possibilities around you, and try choosing to give others the benefit of the doubt some times. most folks are not actually trying to hurt you, but are just getting by in their own ways. just like you.