A: There is an inescapable and undeniable tragedy in Darwinian reality: Life feeds upon itself: Life is a conflict of life-or-death necessities.

Opportunists, cynics and the naïve have long taken this for granted, as a “law of nature,” and hence a carte blanche for doing whatever they will. Psychopaths are not even troubled by questions of right and wrong.

There would be no tragedy if life were just insentient matter; but it’s a fact that many living kinds do feel, and suffer.

In your question you’ve already identified the moral dividing line: necessity. Not convenience or expediency: life-or-death necessity.

An obligate carnivore like a lion or a killer whale has no choice but to hunt and kill. And their prey have no choice but self-defence, including violent, lethal self-defence.

This applies to our own species too, both as predator and as prey. There are still today some subsistence cultures that can only survive by hunting or fishing. There were phases in our evolutionary past when this was true for most of our species.  

But it’s no longer true for most of our species, especially in the prosperous nations. Consuming sentient animals is no longer a vital necessity for most of us. 

So being vegan is right because hurting or killing sentient beings without vital (life-or-death) necessity is wrong. No decent human being can deny this. 

But the criterion is vital necessity, for life or health. (We can still kill in self-defence, and exterminate bed-bugs.) Is biomedical research on sentient animals a life-or-death necessity for humans?

I think you have also identified the answer: “much of animal research feels completely unnecessary.”

Much research – like much of what humans do – is not done because it is vitally necessary for our survival or health. A lot of research – in all fields, not just animal research — is driven by curiosity, careerism, fads & bandwagons, funding, profit, habit, and, frankly, also ignorance and  incompetence. These human foibles are perhaps tolerable or at least understandable where they don’t involve living beings. But where they entail hurting or killing sentient animals, the question must be asked: Is it vitally necessary? Does it save (human) life and health?

It is undeniable, today, that some biomedical research does save lives and health. Covid research is already an example.

So the first part of the answer about biomedical research on animals is that much of it is unnecessary, hence unjustified, but not all of it.

And it has to be added that a call for the immediate abolition of all animal research – just like a call for the immediate abolition of all human consumption of animals – is both unrealistic and unjust. It is not kindness to call for sacrificing sick humans any more then it is kindness to call for the starvation of subsistence cultures (or of obligate nonhuman carnivores). 

But it would be sophistical to cite these prominent exceptional cases as justifications for continuing to allow and support massacring animals for food regardless of whether it is vitally necessary. Or for continuing to allow and support biomedical research without far, far more conscientiously limiting it to what is likely to save lives. (Sophists and corporate interests and their lawyers will of course always try to play on the slippery slope of “likelihood,” but, again, many if not most cases are transparent enough so decent people will see that likelihood is not seriously at issue.)

It might even work against the urgent needs of the tragic number of animal beings who are suffering and dying every minute, everywhere, at human hands, needlessly, to insist that veganism means renouncing the life-saving benefits of medicine too.  To wrap together a call to stop causing needless animal suffering with a call to give up potential medical help can only add to the resistance to renouncing either of them. 

So my approach would be to stress the need to abolish that vast proportion of  biomedical research on animals that is unnecessary or incompetent while focussing on ending the monstrous amount of suffering that humans inflict  on animals gratuitously for food, fashion, finance or fun, without the slightest connection to health or survival needs.