Safety reasons, it's just a flag and he's acting like a diva not even wanting to touch it, he could at least picked it up and handed it to the body guards and not throwing it around using his leg.
I can't believe there are still people rooting for him and even worse now defending him. As somebody else posted other acts take the flags and show respect. But respect doesn't exist in Bieber's dictionary. I have never liked him, never. But he makes it really hard to actually give him any chance to change this opinion. He's just disgusting.