
Calling people gullible while falling for this 'he's an actor' foolishness
Some people laugh when they're nervous about something, e.g. preparing to speak at a press conference. Some people laugh while trying to keep themselves from crying. There's nothing weird about it, other than the fact that it's something that you don't typically see since a lot of people don't have a problem with letting whatever emotion they're feeling show. Going from laughter to tears in a second isn't so unusual.
Example: I just watched a porn video online a few days ago....it was a Facial Abuse video. The bytch in the video was getting fukked very rough and being smacked around, during which she was obviously upset. At the end of the video though, the cameraman was interviewing her, and she was smiling while answering his questions and she seemed okay….almost like she had actually enjoyed the shyt. Then he asked her why she looked upset earlier, and if the rough sex brought back any bad memories…..all of a sudden, the hoe switched up from smiling/chuckling to crying like a fukking baby, tears down her face, and then hyperventilating and physically shaking after a few seconds like she was having a panic attack

. When the cameraman asked her what was wrong, she said she had been raped a lot, and that's why she was upset and trying to mask it
Then she stopped smiling, saying the rape made her a stronger person. Then (as if that wasn't freaky enough), the video ended with the cameraman complimenting her, obviously trying to calm her down and make her feel better…..and she was smiling and laughing again
Point being, her reaction was similar to dude in OP's video, and if you saw the porn video yourself, you'd see that ain't a porn bytch on this planet Earth is THAT good of an actress.
Some people just try to front with laughter when they're upset, because they don't want people to see them upset, or they don't want to look weak (in the case of a man). Unfortunately, not everyone can hold it together for long.