It seems that many non-vegans say: but what about important issues of social justice involving humans? I have 4 comments:

First, being vegan does not require that you stop doing any other good work for all social justice causes. Being vegan just requires that while you are doing those good things, you don't eat, wear, or use animal products.

Second, 99% of the people who ask this question aren't doing anything about the other issues except asking vegans why they are not doing something about them instead of promoting veganism.

Third, veganism--at least as I discuss it--is about nonviolence and violence is what is at the root of all of the other social justice problems.

Fourth, animal agriculture is causing a great deal of human suffering and is exacerbating social injustice.