A supposed biblical times custom.
They are claiming it was a financial transaction... the fellow bought the wife and the wife had no sayso in the matter.
That isn’t historically accurate at least as far as the Abrahamic line went, but it’s a glittery straw man.
A lot of customs have been abandoned and adopted since the Old Testament. It would be impossible, both culturally and legally for a large society to live that way literally.
The LGBT group can keep pretending that they don’t know this.