I want you to take a minute to think about how you are going to answer the following question, or how you do answer it if you have thought about it already.
How are we going to address other sentient beings and their interests? This is a question that everyone should consider, as it is a HUGELY important question to think about and answer consistently! Think about it! We are talking about how we are going to treat tens upon tens of billions (probably trillions; I can't really count that high anyway) of other beings and WHY. Has it ever been good enough to say that I will not even attempt to answer that question? Has it ever been good enough to say that I won't even attempt to be reasonable? Let us hope not for fellow human beings. There are some questions that we do not know the answers to, but those are often physical, metaphysical, or ontological questions. This question is ethical, and easily comprehensible. What are we going to do now that we know that animals are sentient? Some people in the past may have argued that animals are sentient, and hey they were right; however, some of the evidence is, relatively speaking, quite new. The question cannot be avoided. It is out there.
For vegans the answer is clear and logically consistent; granted no one is perfect, but veganism shows an earnest attempt to try to improve, and provides an approach that does not simply disregard the interests of other sentient beings.
What are other possible consistent replies to this question? I have never seen a nonvegan argument that provides a consistently logical answer to the question of how we should address other sentient life. The question is out there. Answer it ...