So it’s made of shit, right? And shit is an animal product. But barring a night of drinking or a particularly aggressive burrito, shitting does not harm the shitter; it’s beneficial and required. Also the animals in question can and do consent, does that make it vegan?
Veganism has nothing to say directly about human/human interactions, but it is based on the principles of compassion, empathy, and respect for life, and a person with those values is not likely to be interested in exploring brand new avenues of human exploitation. Lets say this develops a market of people with a taste for human flesh. But it’s cheaper to get it off a poor person than out of a vat… Let’s just not even explore this.
Veganism isn’t concerned about animal harm but about animal exploitation. This is a difficult thing for many people to grasp and then accept. For example, from a strict point of view (that I take), owning pets is not vegan because it is the ownership and exploitation of an animal for emotional gratification and companionship. As soon as you are getting something out of it, things change in your head. You start lying to yourself in subtle and not so subtle ways. We all have basically the same stupid brain, and it cannot be trusted when it wants something.
So no, even if the animal is not obviously harmed, it’s still not vegan to exploit an animal. However, most people are not this diligent in their conduct, and I suspect a near majority of vegans own animals.