I haven’t read every single post on this topic, so if I am being repetitious, I apologize in advance. While it’s true that Man was created to be vegetarian, the Dor Hamabul altered that state and HaShem permitted us to eat meat (probably because it was due to Noach’s care that they survived the flood), and that permission comes with specific restrictions (only KOSHER meat from non-carnivorous animals, no mixing of meat and milk, etc).
AS frum Jews we accept the concept that Ha-Shem would never give us a mitzvah that would cause harm to us. The Mitzvah of Korban Pesach is VERY specific as a chiyuv to all Jews, who must eat of it and finish the meat before the morning. If we were really supposed to remain vegetarian, Ha-Shem would have made a proviso for that. It is not a suggestion that we eat this meat – it is law. Liekwise there are many korbonos that are mitzvahs to be eaten in a certain place (i.e. Yerushalayim), or for a specific reason, or by a specific person (the kohein or levi). Do vegetarians honestly believe that Ha-Shem meant everyone to follow these mitzvos except for them? We were also created to live forever, but Adam HaRishon and Chava caused us to lose that privilege. We were created to live our lives in Gan Eden, but that too was taken away. Just because Man was created a certain way, does not mean that his own actions could not cause Ha-Shem to modify the original plan.