Why is Vanila ice-cream white and Vanila extract brown?

Vanilla ice cream is made by scraping out the inside of a vanilla bean and mixing it with cream, sugar, eggs and salt. Real vanilla ice cream will have brown flecks in it from the vanilla beans but will be mostly white. Vanilla extract comes from soaking vanilla beans in alcohol to extract the flavor from them. Since the beans are brown, the color from the beans is extracted along with the flavor. That is why vanilla extract is brown.

You can buy clear vanilla extract. I'd say vanilla ice cream is really a cream color.

Because the main ingredients in ice cream are milk and cream. Only a small amount of vanilla extract is used because the flavor is so strong, not enough to change the color of the milk and cream.