SCREAMING MAN

This is from Denver's Pride Parade.  I wonder why he's screaming.  Was it something someone said?  Is the roof of the vehicle too hot?  Is that man squeezing him too hard?

BLOGGER IS FUCKED UP.  WHEN I WANT TO POST, THE PAGE JUST KEEPS LOADING.  I MAY HAVE TO START A NEW FUCKING BLOG BECAUSE OF THIS.  THIS IS TOTALLY FUCKED UP.  HOW DO I REALLY FEEL?