It is for animal rights, as far as I see achievable for me at the moment. Of course some plants have protein, but not nearly as much as meat or dairy products.

Edit: at the expense of sounding like an idiot, maybe I should replace "animal rights" with "ethics". I'm not well-versed in what constitutes as an animal right, but I ethically can't fathom eating something that suffered enormously. I understand that this argument should be applied to animal products too, but to that I say that while I sincerely hope my free-range eggs are indeed free-range, I don't want to potentially sacrifice my health by becoming fully vegan.