You're not supposed to use reason when you're talking about Broly. You're only allowed to use hunches, the least canon media you can find and multipliers you made up yourself, while repeatedly saying that Broly is the Legendary Super Saiyan like that justifies everything. You also have to ignore Broly: Second Coming, since that involves a single, relatively weak character putting up a good fight, which would destroy the legend of Broly the Infallible, Eternal Master of the Dragon Ball Omniverse and the guy who hides inside Magetta and who can beat SSJ4 Gogeta and Zeno at the same time in his base form.
At least, that's what I've seen on the Internet. Am I wrong about this?