Consent doesn't apply to animals though.
Short answer: We protect humans who can't consent, babies, the severely impaired, more, not less. Inability to consent is a reason for care, not a free pass.
We already protect the humans who can't consent. The question was never whether a being can say yes, only whether it can be harmed.
The objection
“Consent is a human concept. Animals can’t give it or withhold it, so it makes no sense to say we’re violating it by using them. The whole framing is a category error.”
The answer
You’re right that an animal can’t sign a contract, and that’s exactly where the argument turns against you. The question that matters is whether a being can be harmed. Consent matters because beings have interests that can be set back; it’s a tool for protecting those interests, not the source of them.
Look at how we already treat the humans who can’t consent. A newborn can’t consent. A person in a coma or with profound cognitive disability can’t consent. We don’t conclude that we may therefore do whatever we like to them. We conclude the opposite. Inability to consent makes someone more vulnerable, and we respond with more protection. We act in their interests precisely because they can’t speak for themselves.
Apply the same standard honestly. A pig, a cow, a chicken has interests in not suffering, in not being confined, in going on living, and the science of animal consciousness now backs this across all vertebrates and many invertebrates. The fact that the animal can’t say “no” doesn’t dissolve those interests; it just removes its ability to defend them. That is a reason for restraint, not for exploitation.
So “consent doesn’t apply” quietly switches the question. It treats the absence of a “yes” as if it were a “yes.” But silence is not permission, least of all from a being that would clearly refuse if it could, as any animal struggling at the slaughterhouse door demonstrates. The capacity to harm someone is enough to wrong them. Their consent was never the thing that mattered.