Why? We dunno. Except that he thinks someone is pulling his leg about science things. And he likes to look like a big man.
Sadly, no one paid any attention to him and the couple of reporters who wandered by during his "speech" spent more time trying to figure out how to spell his name than report on what he said.
One "F" or two? I know what "F" I'm giving him. And it's a big one.
Less snarkily, if a Democratic Senator had done something similar while Bush reigned supreme, going to another country where our President was speakifying importantly, just to slam his policies and take our internal politics across outside our borders...well, he or she would have been crucified by the right and the Rethuglicans and the media would have spent days reacting in horror.
Today, as my trolls like to say, crickets. IOKIYAR, ain't it. At least one thing never changes.