I wonder if other languages are less ambiguous about this. "Steve Wozniak cheered" makes it sound like he did the cheering. But the practice of removing verbs from headlines makes this more ambiguous. "Car collides with bridge" is not a grammatically correct sentence but a perfectly normal headline.

But in this case, "Steve Wozniak cheered after telling students they have AI" _is_ a grammatically correct sentence, which means that Wozniak did the cheering, which may be the source of confusion. Or, perhaps it means not that he vocally cheered, but was cheered up emotionally.