Exploitation and the asymmetry between humans and non-human animals
Many vegans argue along the lines that non-human animals should be treated in ways that we typically treat marginal case humans. The argument is that severely disabled humans who have the same (or similar) subjective experience as animals are still afforded basic rights and dignity and there is no morally significant difference between marginal case humans and non-human animals; therefore, we should afford basic rights and dignity to non-human animals.
However, I'd argue that this intuition doesn't actually hold in all cases, even for vegans who would typically use this line of reasoning.
My example is taking pictures of naked people without their consent vs taking pictures of naked non-human animals without their consent. If I secretly took a picture of a naked human and posted it online, we would think I wronged this human in a significant way, even if the human was mentally disabled such that they couldn't feel wronged by the action.
However, many people, including vegans, take pictures of naked animals and post them online all the time. No one, including vegans, feels that this is a form of exploitation. This is a very big asymmetry that requires accounting for.
One possible answer is that even if a human is severely disabled and is unable to feel wronged by the action, they are still participating in a society where such an action is viewed by society as degrading to those humans. Therefore, although the action might not cause those humans to experience any suffering, they are still suffering reputational damage as people in our society.
Non-human animals are not participants in our society in the same way as people (even severely disabled ones). If I post a picture of my naked dog online, this doesn't cause my dog any reputational damage in society. In fact, my dog may be considered cute and benefit reputationally. It would also not be considered exploitative to my dog if I monetized pictures of her.
Additionally, because the human did not consent to the photo being taken may be seen as a violation of the human's privacy and dignity. However, photographing and filming wildlife without their consent is not something that is considered wrong by the vast majority of people, including vegans. In fact many people, including vegans, enjoy watching videos and photos of naked animals without their consent.
But it seems clear that there is an asymmetry between the sorts of things that might harm a human (even a severely mentally disabled one) and the sorts of things that might harm a non-human animal.
I think that this difference can also extend to other areas where we treat animals differently but in ways that don't necessarily harm them but benefit us. For example, a non-invasive and non-harmful extraction of a few cells from an animal would benefit us greatly when it comes to lab-grown meat, and it can be done in a way in which the animal is indifferent to the action. Many vegans are against this because the animal can't consent, and the animal is being used. Vegans will then compare doing this to a human and claim that it is non-vegan, morally wrong, and an instance of exploitation.
I'd argue that there isn't a one-to-one correspondence between what counts as an instance of exploitation to a human and what counts as an instance of exploitation to a non-human animal. If vegans agree that it is exploitative to monetize pictures of naked humans without their consent, but it isn't exploitative to monetize pictures of naked animals without their consent, then it seems like vegans agree with this as well.
Then why should we consider it to be an instance of exploitation to take a few cells from an animal for our purposes if the animal is indifferent to the act? It seems no more exploitative than monetizing a picture of a naked animal (which is already deemed to be acceptable and unharmful to animals).