People always try to assign a reason to things. We don't like accepting that there just aren't any reasons. But as someone who has seen bitcoin go up and down and back again over years, there really isn't a reason for it besides "people decided to buy or sell." And those people aren't operating with logic. It's speculation.
People were saying the exact same things about Silk Road. If Silk Road closes, bitcoin will go down! Nope, didn't happen.