@Melee
No need to add the "u" in my name; I left it out on purpose.
![Stick out tongue :P :P](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f61b.png)
But on your assertion: Goku could absolutely go all out and throw at the same time. Bergamo gains power based off of the attacks thrown at him, yet he can only increase gradually. He could have gradually powered up alongside Bergamo, giving him enough strength to stand up to max out SSBKKx10.
If Diashinkan/Zen'o had called out Goku for staying in SSJ for so long, I may have agreed with you. If they said "go all out, we know you can do more than that" then sure, he has to go straight to max. But he is told no such thing is allowed to remain in SSJ for a long time. He could have climbed his transformation ladder and fed Bergamo power, which he was already allowed to do. Bergamo almost beat out the jump from SSJ to SSBKK. If Goku had gone SSJ2/SSJ3 or even just normal SSB Bergamo probably could have contested him when he was forced to go all-out.
And no, only Goku is accountable out of the Z-Fighters. Their opponent didn't make a multiverse saving deal with Zen'o. Goku's did. If Lavender and Basil had made the same deal, then yes, they would share blame.
EDIT: On a second read it seems like you did not watch the episode.
"Which brings me to another point. Goku could very well hold back for moral reasons, but that doesn't mean the other 70 fighters who are not from U9 will. It would be completely moot, and he would still run the risk of his own universe and six other universes getting erased. The best thing Goku can do in his position is save his own universe. That's his least risky option. And so far, he's doing a better job than other warrior from their respective universe."
The other 70 fighters don't matter whatsoever here. Bergamo made a deal that if he beat Goku (not needing to beat any other fighters, just Goku) then Zen'o would rescind his decision.
"Once I have defeated this man, please rescind your rule to erase the defeated universes!"
Zen'o then accepts. If Goku threw his exhibition match against Bergamo in a convincing fashion (which I have asserted he could), literally no one dies. He disregards the notion of this altogether and acts nonchalant in the face of his condemnation of the universes via victory.