i agree with sabret00the
in addition (doesn't seem fitting) with usopp that knew merry couldn't sail anymore (he told it to franky in his base) and acted like he heard for the first time when luffy told him and questioned luffy's way of seeing things along with his leadership AND started the fight
so it isn't the same
I think, quite frankly, that this is precisely what makes people defending Usopp's insubordination so ridiculous. He KNEW Merry couldn't sail anymore, acted surprised when Lufy told them, then started the fight.
Before reading some of the responses on this thread, I didn't really realize how much I was pissed off at Usopp's immaturity and yes - his pride. Usopp started the fight, repeatedly insulted and cast doubt on his captain and best friend because of his insecurities, then said he wasn't a real captain. Then challenged him to a duel - serious business, amongst men.
Then, because of his pride, put on his Sogeking mask - and while he did try and convince Robin to trust Luffy, and contributed during the Enies Lobby assault (the extent of which people will differ on) - he still spent the whole time putting on airs and doing his childish "I-am-a-hero-wish-fulfillment" act. Now he comes back, and at first he tries to ease his way back onto the crew to gloss over just how out of line he was. While I don't doubt that the apology was sincere - ugh, what a way to get to it. What a trainwreck of an arc for my opinion of Usopp.