No lamb on Pesach: the real reason

Recently I presented an argument for why Jews shouldn't eat lamb on Pesach.  This morning I realized I forgot to highlight an essential gloss on the traditional argument...from my very own family.  This one comes from my Grandma:

The wise [son], what does he say? "What are the testimonies, the statutes and the laws which the L-rd, our G-d, has commanded you?" You, in turn, shall instruct him in the laws of Pesach, [saying] `one is not to eat any dessert after the Pesach-lamb.'*

To this passage my Grandma always comments: "And that's why we don't eat lamb!"

Hag Pesach Sameach, friends.

(* My family always uses the Maxwell House haggadah; since I didn't have mine handy, the quote is from Sichos In English.)