They admitted their war crimes and laughed at the same time. Some are implying they think raping and killing is funny, but I don't think that. I think some people laugh when they admit something they know they did was wrong. Like laughing at their self embarrassment.
This is why Israel has to lie about Palestinians raping. Because that is what the Israelis did. If you are doing an internet search for raping it is best that the lies come up in your search instead of the truth.