I haven’t read everything fully what Sri Aurobindo has written about non veg, but I came across something saying that eating non-vegetarian food is not so bad. However, the Mother has a different view. I don’t remember her exact words, but she believes it is not right🤨.

Yogis are way above these ideas anyways. Sri Ramakrishna loved prawns. Swami Vivekanand ate meat. How does it matter as long as they realised God within which , i am afraid many vegetarians do not even bother about. This is what Swami Vivekanand and Sri Aurobindo cautioned about, the narrower Hinduism of the kitchen and the cooking pot which stops at cleansing the body but cares little to cleanse the mind and soul. 

And also, Some non-vegetarians say that we cannot be sure animals feel more pain than plants, and they ask how we can know about their suffering. They also question whose suffering is greater and how do you know that animals feel more pain than plants.

It is not about life or about suffering. It is about the consciousness embedded within what is being eaten. Plants contain life that sustains matter which is what is needed. Lower animals contain the sting of pain. But the higher animals which is generally not to be eaten, the quadrupeds, is because they have emptions and experience fear, rage, grief which is not good for the one consuming it, especially when the process of taking life is deliberate and slow as in halal. It is a cruel act and keeps us tied to the animal state. Hence the prescription. 

Affectionately,

Alok Da