Not sure what you mean by sexism.

But there are differences in the sexes with regards to the process of conceiving and rearing a child. And it seems to me that a big part of our social constructs that were developed to deal with those differences can be reduced to "the man doing something expensive and hard to fake". Which isn't really that different from "the man proving she matters to him by buying something".

A dowry is a social construct not a "difference in the sexes"

And there are plenty of women who find this custom distasteful. Some women want a wedding which displays opulence and in which they are treated like a princess. Others want one which more implies the equality of the wedding partners in responsibility and capability. Others want a humorous circus or something that emphasizes the roles of their community in their future lives. Many don't want to start their married life, or any stage of life, with a financial setback.

Oh, agreed. I'm just saying what the social environment is. The environment boys grow up in is just as toxic, if not more so, for entirely different reasons.