Yes, I agree that it would be wonderful if ahimsa was part of all religions. But we have to work with what exists.
And I think the problem is the human tendency to misuse teachings and to find rationales for their actions.
For example, democracy is a wonderful concept, but it has not prevented democratic US from backing dictators and starting unjust wars to further our aims.
Capitalism ideally could be wonderful, but it has led the world to a severe recession, much unemployment and a potential climate catastrophe that threatens all of life on earth.
Similarly, dominion if properly understood as responsible stewardship COULD lead to far better conditions for animals. But people choose to take it as a license to exploit the planet and harm animals.
I have argued for years that Jews should be vegans, should not wear fur, should not experiment on animals, etc., but without much success.
And there are plenty who try to discredit me and JVNA by arguing that we are trying to start a new religion. So, I do not think I would get very far promoting ahimsa -- it would be counterproductive.
Gotta run now, but this summarizes some key points that I think should be considered.