Eye for an Eye / Tu Quoque Fallacy
You used a tu quoque fallacy to defend the exploitation of animals.
The idea that because a vegan did something wrong in some way, therefore it is okay to harm animals. A common example here is “plants feel pain” and since vegans kill plants it’s okay to cause animals pain. Another example is pointing to human injustices in the supply chain of plant foods as a reason that it’s okay to perpetuate harm to animals. From a logical perspective, two wrongs don’t make a right.
Furthermore, the case that plants truly experience suffering is very weak as is explained in detail in this video.