No racism intended, but why do some white people feel inclined to touch a black persons hair...?

Or ask if it is "real or fake". Like there are a lot of black girls at my school that have long hair, but by far my friend Alissa hase the most beautiful! It falls down past the middle of her back, brown, and just healthy looking. She is same skin color as gabrielle union. Her hair has grown a lot since last year and every day, no one fails to ask her "is it real?" and run their hands through her hair or tug at it! There where these two white girls today in athletics and one asked and the other was lik "no it is extensions" and alissa was like "um yeah it is all my real hair, not extensions". I thought that was just incredibly rude to ask someone or to insist. I have seen stuff like this only so many times. Not saying that they all do it, but some really do. Don't call me racist because I am half white, but I am just wondering.