Feminist proof that men owned women?

In a debate on gay marriage a feminist using the name "Min of Billinudgel" decided to throw in some patriarchy theory. She claimed that until recent times marriage was based on property rights for men:

Example: a man’s goods and chat(t)els - hence the reason that widows were until recently described as chatelaines. That is, the wife and the kids were/are defined as ‘moveable property’.

Min's idea is that widows were called chatelaines, that chatelaine derives from the word chattel, and that this proves that women were/are treated in marriage as men's property.

The proper response to these kind of feminist arguments is scepticism. A little research usually proves them false.

So what is the origin of the word chatelaine? It is part of a pair: a chatelain is the male keeper of a castle, a chatelaine the female mistress of a castle (or country house). So Min's argument can't work, as the word was applied in a similar way to both men and women.

Widows were sometimes called chatelaines, but in a literary sense of a woman who found herself running a country house, e.g. "Mrs Gareth, widowed chatelaine of Poynton, is fighting to keep her house with its priceless objets d'art ..."

Why would Min want to believe that women existed as male property? It fits patriarchy theory: the belief that autonomy makes us human, that men have autonomy at the expense of women, that women are therefore not treated as fully and equally human, and that this is due to men organising society to oppress and dominate women.

It's a dismal theory in that it assumes the worst about society: that past generations of women have not had a fully human existence, that men have acted in bad faith toward women, and that institutions like marriage are based not on heterosexual love or an ideal of family life but on issues of power and gender conflict.

Min made one other contribution to the debate. Someone had suggested that if gay marriage were to be permitted because it had become socially acceptable, then so too might polygamy or incest one day gain social acceptance and therefore have to be made legal. Min replied:

The reason that a number of sexual practices are not acceptable, such as incest is because there is the element that one of the partners to the relationship would be a victim of coercion.

Likewise with polygamy. While some people might be quite happy within a polygamous relationship, there are a number of examples especially in fundamentalist religions of younger members being coerced into becoming junior wives and therefore subordinate to the senior wife - and especially the coercion element, that is in spite of the girl’s own wishes.

Obviously, very obviously the same rule of law would apply to same sex marriages - that a marriage is null and void should there be an element of coercion prior to entering into the marriage.

Min is apparently a modernist when it comes to morality. She believes that everything is moral if it is freely chosen. Therefore, the only way to legitimately oppose a practice like polygamy is to argue that it is coerced in some way.

It's not an approach that is likely to maintain any existing standard: a polygamist would merely need to display the free consent of his wives to have his marriage endorsed as moral. Min's approach to morality would not only lead to an acceptance of gay marriage, but to nearly any conceivable kind of marriage.