Oh, I'll have to admit, for some reason I didn't consider the meme when interpreting your comment, thought you were just answering to the title of the post.

Personally, I think that a charitable society should strive towards being compassionate to all sentient beings. It's understandable and even necessary to our survival that we put ourselves first, but we're at a point where we could easily diminish a huge chunk of pain and suffering from animals just with the mild inconvenience of changing our eating habits. That's one of the better points the meme makes, the drawback isn't some unacceptable sacrifice.

If you are asking me: “when do you think veganism makes a good case?” then I would say: when it makes the point that if we don’t switch our diet we would end up destroying ourselves, since our current diet does not seem to be sustainable long term for our environment.

That's a great argument to go plant-based, but veganism, by definition, is about reducing animal exploitation "as far as possible and practicable" (according to the vegan society who invented the term). Note that there's leeway for compromise.