My title is the title of the article. The phrasing is vague because it's unclear exactly what "struck" means. The first half of the article describes the incident.

The Saint Louis Chess Club announced Wednesday night that 17-year-old grandmaster Christopher Yoo had been expelled from the U.S. Chess Championships for "gross violations of our Code of Conduct and the U.S, Chess Safe Play Policy" after he crumpled up his scorecard, stormed off, and allegedly "struck a videographer from behind" following his fifth-round loss to Fabiano Caruana. Per local NBC station KSDK, the cops said that Yoo was arrested and charged with fourth-degree assault.

They identified the victim as a 24-year-old woman and confirmed that Yoo was released as the case will be dealt with in the juvenile court system. While Yoo's scorecard meltdown was captured on video, no recording of the full incident has been made public from which we can contextualize the somewhat vague verb "struck."

This has prompted some players such as former World Championship challenger Ian Nepomniatchi to wonder whether Yoo getting fully booted from the tournament was an overreaction. That's a fair question—though, according to both KSDK and arbiter Chris Bird, Yoo outright punched the videographer, with Bird calling the punch "completely unprovoked, from behind and in no way accidental."

Levon Aronian, currently competing in the championships, said he saw a video of the "awful" punch and called it a "well prepared punch to a completely innocent person."

https://defector.com/teenage-grandmaster-christopher-yoo-booted-from-u-s-championships-arrested-after-post-loss-meltdown