A giggle is a silly laugh, usually quite light. and repetitive. A chuckle is a repressed, quiet laugh. They are both types of laughs. So you can’t compare a giggle to a laugh, cuz in actuality a giggle is just a type of laugh. But what makes the biggest difference is that people usually use a giggle to describe a baby laughing or some type of innocent being. You don’t ever here saying that a baby chuckled. So it’s just usually a pet peeve when someone sees the world giggle to describe a laugh. Not that there’s any deep meaning behind why we hate it so much, simply that it gets under our skin.