LORELAI: If you had your way, Mother, you’d lock us up like veal. That’s what she wants, veal children.
Veal is the meat of calves, rather than beef, which comes from adult cattle. In the past, many calves raised for veal in North America were raised in small crates, often tethered, which is what I think Lorelai means by keeping them locked up like veal. In the 2000s, this cruel practice began gradually to be abandoned in favour of slightly less cruel practices, and by 2017, all members of the American Veal Association raised their veal calves untethered in pens, not crates.
Note that Lorelai implies that both herself and Rory are Emily’s children, as if they are sisters, rather than mother and daughter, and as if Lorelai is still a child.
(Lorelai enjoyed a meal of ossobucco made by Max, a veal dish).