Time will come in this Kali-yuga when actually people will become what is called man-eater. Still there are existence man-eaters in Africa. So the human society is coming to that position. Like animal, they will eat their own sons and daughters. So therefore this practice, unnecessarily killing animal, is the one of the pillar of sinful life.
Striyaḥ sūnā pāna dyūta. Pāna means intoxication. We are already intoxicated by illusion. Because we are in the material world, we are accepting false things. Just like this body. I am accepting I am this body. This is intoxication. I am soul, I am Brahma, but I am accepting this body that I am this body. This is already intoxication. And if you increase more intoxication, then where is the possibility of getting real knowledge, brahma-jñāna?
So the pāna, intoxication, should be avoided. Animal killing should be avoided. Illicit connection with woman should be avoided. And gambling, speculation, fatkabaz (gambler), that should be eliminated, avoided. Then you get the chance of becoming pure. And without being pure, you cannot be engaged in the loving service of the Lord. The Lord is pure. Paraṁ brahma paraṁ dhāma pavitraṁ paramaṁ bhavān (BG 10.12). So you cannot approach Lord being impure. Even I do not indulge in illicit sex life or meat-eating or very much moralist, still I am impure if I think myself "I am Indian," "I am American," "I am Hindu," "I am Muslim." These are also impurities.