Stating that the probability is zero when we simply don't know what the probabilities are does seem like an extraordinary claim.
Imagine how reassuring it would be to people if we had evidence that there's no existential risk?
There's an opportunity cost in the doomsday prophesying, though.
The media coverage of "these extremely capable robots might kill us (according to the guys who sell the robots)" comes at the cost of coverage of the real, present issues surrounding the tech oligarchs that we're already facing.
Sure, there are some failure modes that lead to some really bad stuff, but human extinction seems exceedingly unlikely to be one of them, and "10%" is pulled straight out of Dario's derriere.
Far more likely are economic disruptions that impact the tenuous balance between labor and capital and lead to unpredictable societal upheaval.