" Why does UPI print a story without verifying it?"
1. They are UPI. And your problem with that is?
2. The UPI Moscow bureau is basically some dude who translates Novi articles, and slaps UPI's name on it. (It is legit -- Novi gets paid.) The language in the original was a little ambiguous. If you were up on Russian you knew what they meant . . . but if you did not know Russian inside out, it was easy to misinterpret.
Note that the original Russian-language version WAS correct and HAD been verified. The problem was a mistranslation of the original text.
Nothing - except I expect more from a professional international news agency, like verifying the story with American sources.