What makes you impure?

Once upon a time a lion catches a young man who had just got married.
“Please leave me, I have just got married I want to enjoy life a little more”, pleaded the young man.
“No, I can’t do that, but I will give you two options:-
1) I will eat you only after killing you.
2) I will eat you alive part by part, so that when I eat each part of your body, eg: your legs, hands etc. you will feel the pain” replied the lion.
If you were in the young man’s place which option would you have chosen? Of course, 90 percent of us would select the the first option.
Suppose you kill a hen and put it to the ground after a few days you will find only the skeleton.
Cut a potato in half and put it on the ground after a few days it will grow up into a potato plant.
So you exercise the first option of the lion when you are eating non vegetarian, food and the second option when you are eating vegetarian food.
When you are chopping the potato or any vegetables for your dish it is crying loudly in a voice you can’t hear, till it goes inside the frying pan. Do you have any idea how much pain and stress the potato undergoes? Because you cannot hear the potato scream you think your act is justifiable?
How will you justify this if you are vegetarian just because you are against killing and you look down on the non vegetarians?
It is not what goes into your mouth and then your stomach that makes you impure, but what comes out of your mouth as rude words and your evil thoughts and your evil actions that make you impure.