Isn’t that in the Torah?

Exodus. Exodus is part of the Old Testament, along with Leviticus.

Leviticus (11:9-12) is where shellfish are banned, mixed seed or fabrics (19:19) It is where modern Christians cherry-pick their justifications on being anti-LGBTQ. (Lev. 18:22, 20:13)

Point is, they cherry-pick from the Old Testament when it suits them, and if you look at the rest of the rules in the books they reference that they ignore (e.g. tattoos, touching pig skin, eating pork, shellfish, etc. etc. ) it’s totally fair game to point out the rules they ignore in the same books as the ones they cite.