@Echonic Because it is a world through a child's view. The way children view the world is different from us. There is also the cutural difference.
@mase_aga Actually, most Asian adults do that to show the child that they can't drink it. If you didn't let them, they would just be curious and try to taste it themselves. My father let me tasted beer and wine when I was a kid. Not a fan of wine still this day but I developed a liking for cold draft beer.