You don't say:)
Women gave other women disingenuous beauty advice about their hair, sabotaging their attractiveness.
I used to have long and thick hair. Long enough to sit on, if I let it loose. My sister always told me "you should do something to your hair, you will NEVER get a boyfriend if your just keep your hair long and braided." Concidering how many men have actual fetish over a long hair, and practically ALL of them prefer long hair on woman, I find that interesting tip to give your younger sister. BTW why almost all middle-aged women cut their hair? They start looking really manly, in the age where we start to loose some of our femininity anyway. I realize the hair does get thinner, but even thinning hair looks nice and neat on a tidy bun. It also saves tons of money.
I've seen older women doing it to young girls. Mirror, mirror on the wall was based on a real story:)
As for your 2nd point, probably laziness and the desire to stick it to her husband.