This attack doesn't create a regular beam struggle[]
First, note the name "penetrator". Second, note how it literally went through Goku's Kamehameha, straight to the source. There was no beam struggle in the usual sense; the attack is designed to punch through ki waves.
EDIT: This is relevant because the article basically says that Bergamo was able to hold his own against SSB: KK Goku in a beam struggle, when in fact, Bergamo's attack almost completely takes Goku's attack out of the equation because of the way it works.