Why do people make fun of others for crying?

Even though Im mean as hell I don't even do that because thats childish man the best thang fo a person to do is be like aye man yo aight not laugh and shiiiittt .. Shiiiit even i cried before . People just aint got a heart ... Hell why am I even sayn this I dont either but I know when to not cross the line when someone is hurt like cry .