User blog comment:CNBA3/Chapter 405 Review/@comment-4829046-20141020120040/@comment-4829046-20141021122131

What Goku did was not worse. Granted Vegeta went too far though.

If you were a seasoned fighter in those circumstances, you would also want to fight someone at their full potential. That's kind of the point of a direct fight, otherwise you could use underhanded tactics or even assassination techniques and cheats like blowing up the planet instantly. You probably get that chance only once out of hundreds of fights so makes sense you want to get the most out of it before it is over. Nothing sucks more than not having a big hurdle to overcome when you are a battle-hungry warrior. Especially if you are aiming for peace/control/stability, which undoubtedly means you decrease the amount of serious fighting you can do. Which is why some characters prefer not to defeat all their opponents completely. That way they can bounce back, rebuild their forces and once again come for the slaughter. This can apply regardless of moral views.

In this instance, Natsu did NOT do that. For one thing, his reasoning was "my dad told me to, so I won't need any help". Granted this sounds like a Gohan scenario, but at least Gohan would understand that he needs help in defeating such an opponent who so far hadn't even taken a scratch. In previous instances after the Laxus fight, Natsu had good reasons for soloing the big baddies of the arc, but this was utter bullshit. This is just a copy-paste of his battle with the Twin Dragons except this time we know for a fact that Marde isn't as weak.