Hmm. Interesting thread. I'm what I've decided to call a "pragmatic vegan", thoughI'm open to better suggestions. My basic life philosophy is one of striving for harm minimisation. Many things of course, minimise harm in one area and increase it in another, so it's a balancing trick of course ... and like everything else, subject to motivated reasoning.
In practise it means I try to minimise the harm I cause in the world. With regards to eating animal products, in today's world it's a massive harm on multiple vectors - incl ethical, health, economic, environment - so stopping eating meat is really a no brainer. That said, last year I was on a long-haul flight, they screwed up my (vegan) meal order. I've researched and found any uneaten meals would just be thrown away ... and I'd eventually need to get calories somewhere else. Easy decision, I ate the chicken and rice. To do otherwise would cause more harm.
Similiar I have "rescue chickens". These are chickens that were otherwise going to be killed. I've taken them in, housed them, feed them, they have a great life. They lay eggs. So I eat them. To waste them would do more harm. I won't buy commercial eggs and I avoid whenever possible products with egg in them. Same with dairy.
In theory harm minimisation extends beyond living beings, but it's generally universal that all living things want to continue living, so I'd prefer to honour that when possible. This of course
does extend to plants, but reality is I have to eat something, so what causes the least overall harm? Hopefully one day we'll have Star Trek replicators and I can skip killing the plants (and everything else that dies in their production as food)
In the west today it's ridiculously easy to be vegetarian or vegan. So I am.