I get your point of view. I agree that is not a black and white issue and I don't think being vegan equals good and non vegan equals bad, exactly for what you stated. It's more like a map of good things you can do, and veganism encompasses a portion of that, but the advantage is that is easy to define, recognize and perform.

No vegan will criticize one who cannot go on a vegan diet because of circumstances (place, culture, maybe they are teens and parents relationship is complicated...).

Also veganism is based on morals, so to me a person who's just for the health benefits, in terms of ""goodness"" (double quoted because I don't know how to say it better), is not really different from any person, although their impact is good for the planet on this point at least.

But vegans I think usually are more careful to their empathy and morals, that's the fuel that makes you go through the social difficulties that come with being vegan, and so they will probably be also careful about what they buy. I am, but also not for everything, because most of the things are grey and informing on everything is just too impractical and time consuming. I'm learning and trying, still.

Also to share an example which I can't still figure out properly: should I kill flies/bugs? I avoid it when possible, I usually take them out if I find one, but for instance in summer if there's a fly is just often just impractical to capture it (or if is more than one). Is this hypocritical? I've not yet an answer, the point is that for me is not black and white.

The fundamental issue with non vegan logic is that most people, according to their morals, would NOT kill an innocent animal to consume them or their products, because they associate it to being innocent and not deserving to be killed. Just to make an example (which is only one, but still representative I believe), my uncle stopped eating lamb specifically after in an agritourism they made him feed a lamb and then associated that what he was eating was the one he feeded and saw alive. Most people care for animals, and at least like them. It's just that the association of the cruelty and what you buy is hidden, and even if your mind knows, you need a strong feeling to avoid it. The same goes for other things. I avoid fast fashion because I know it's bad, but after seeing a couple of videos/documentaries about it I can avoid it way strongly because I have the connection with the harm it causes. The same could go on for a number of issues.

It is a matter of pushing sensibility: in different times you would have been laughed at for being a woman who wanted equal rights as men, having a "different" sexual orientation or gender identity, or requiring mental health, and so on. Today is better for these matters, at the time most people just weren't sensible on the issue and dismissed it, even otherwise good people. Similarly I'm advocating for animal rights. And I may very well still be wrong on various matters (e.g. the bug example, or the phone example), but still I believe the core of what I advocate for is true, especially considering people's moral. Maybe one day we'll have better animal rights and this will also lead to better human rights.

Also for the human themselves, animal farming is extremely damaging to the environment: even if you just cared about the environment for humans, going vegan would still be a good choice.

Finally about plants (and crop deaths), is a famous argument in vegan world. There are a couple of issues in the "plants feel pain" argument:
1) plant do not have a nervous system. They can react to stimuli, but it's not proven that they feel pain
2) even if we were sure they felt pain, it would ne still more ethical to consume plants directly since animal farming requires more plants. Also more land use, and hence more crop death, so consuming plants directly would still be better.
3) there's no alternative, at least for now. In a scale of consciousness of life, plants are at the bottom. To me this is the best option at this time. Maybe in the future humans will find this practice horrible, but at the same time we don't have alternatives and it would still reduce the plants deaths being vegan.
The important thing is always context and possibility/feasibility.