Karma has nothing to do there. They knew it wouldn't work (or it had to be completely rebuilt), were out of funds and decided to get rid of it, it was taking a lot of room in the hangar since 20 years. At least it was the opportunity to enhance the reliability of the Zenit-2, which performed perfectly.
:rofl:
Chinese were very naïve there (surprising), or it was just another mischevious plan of satellite insurance fraud (more believable).
More like there's no other choice: the Americans would refuse to carry it at any cost, while the other players in the field (Europeans/Japanese) have no Mars missions for the next few years. The Chinese have the ability to launch it directly towards Mars, but they lack the DSN for tracking and relaying data, so the only option is to hop on a non-American Mars mission, and that means the Phobos-Grunt. Mind you, I am not sure that the Chinese are too happy with the Russian way to Mars...