Have been reading about this on the guardian the last couple of days and it's mind boggling how a professional racer could come up with that. The first instinct is that he wanted to pass and slow the other one in a reckless manner, but after reading about it it seems more likely he intentionally wanted to harm him.
There are rare events in sports where I don't think a ban, even a life ban, does justice. Fenati should be put in front of a proper judge for attempting to cause serious bodily harm (not sure that's the proper term to describe it).