I dont know about your location but here in america many grew up watching tv shows like candid camera, americans funniest vidoes and now there is a show called tosh.o and others that show things like people in odd situations or stunts or falling\getting hurt and the shows sensationalize it and promote those situaitons as funny. unfortunately because of this we have many that grew up and many now growing up where it is normal now to laugh and giggle when someone else falls or get hurt in some way. some people are even doing real dangerous stunts\challenges in promoting getting hurt is funny. a recent situation in the news is the teens and adults cinnimon challenge, ice challence and more recently take a selfie with a loaded gun and hope it doesnt go off, all of these "challenges" are promoted as funny when someone actually getshurt by them.

my own opinion is if you find you are giggling and laughing at others getting hurt its time to step back and get in touch with the saying of how would I feel in the same situation. example yesterday i was looking out my window and saw a man trip and fall. myfirst instinct was that was funny started to giggle. but then I stepped back from the window and thought if that had been me what would i have felt and needed. then I went out and helped the gentleman gather his things, collected his dog for him and made sure he didnt need medical help.

in this normalizing people getting hurt era we live in its usually not part of a mental disorder anymore when someone giggles or laughs at others getting hurt. in my location this is more a reeducation of manners, morality and such.

in my location when it is part of a mental disorder for example the mental disorder problem known as lack of affect is a situation where a person doesnt show emotions (all emotions, not just one) or shows emotions in the wrong way, example laughing crying at the wrong times, numb and lack of emotions but it doesnt center on just one thing, it carries over to all aspects of a persons life.