@Daz:
I'll try my best not to argue semantics, but this^ all hinges on that very odd moment where Luffy stated his explicit intentions to be free and go on adventures as they happe- I mean, seek out the Super Bosses of the world and beat them.
It isn't really like with Vivi, where Luffy was doing everything as a friendly favor; when Law asked "Luffy, do you want to team up in elaborate machinations to take out the geopolitical heavy hitters?" the reply was "sure, I was gonna take out the geopolitical heavy hitters anyway eventually, even though-as far and I and the readersknow- this is in no way a requirenment for finding Raftel"
Luffy didn't need to go poke Doflamingo to continue his adventure, he didn't need the alliance with Law to proceed either, and his speech here makes about as much sense as if he'd berated Crocodile for hindering his progress. Oda has done the "Luffy is in wrong place at wrong time and villain obstructs his path" angle many times; this is not one where it applies.
(1) He kind of did berate crocodile. Towards the end, he was saying things like "I will surpass you!" This ties into…
(2) Being the man with the most freedom in the world isn't only about the one piece. It's also about overcoming people who attempt to inhibit freedom - All the main villains share this theme of inhibiting someone's freedom or choices. But, I agree with the general point: Usually, the villain attempts to inhibit the freedoms of some friend of Luffy's; this arc has Luffy's motivations being a bit more vague, with some tie ins to the toys, Rebecca, blah blah blah. Still, at the end of the day, if he wants to be the man with the most freedom in the world, he will have to surpass people who try to inhibit the freedom of him and others.
Lastly: Luffy is Nietzche's sovereign individual. The sovereign individual does not do things because they make sense, but simply because he wants to do them (even that is maybe too strong: the sovereign individual just does what he does).