The lysine contingency - it's intended to prevent the spread of the animals is case they ever got off the island.
Dr. Wu inserted a gene that makes a single faulty enzyme in protein metabolism.
The animals can't manufacture the amino acid lysine. Unless they're continually supplied with lysine by us, they'll slip into a coma and die.
Like you, I used to think the world was this great place where everybody lived by the same standards I did.