Yes, a decent world state should be able to accommodate such collective enterprises, in some fashion. I don't know any of them would need an army, though, and I can't regard it as oppression to deny them the legal and moral right to wage war.
Technically, the barest minimum of a world state could be a Kellog-Briand style pact with a really existing enforcement mechanism. I can't imagine even the barest sketch of how such a sovereign authority can exist in a world of contemporary states merely divested of a legal and moral right to wage war. But if some one could give us a clue? The real point of this thread is the OP's claim that such a state would be a Bad Thing and shouldn't even be an ideal to aspire to. Despite all the posts and asides I haven't seen the barest hint of an argument besides, basically, "because!"
It's largely in the organizing principles.
"As for the Confederation's federalism, this is not merely an aspiration or ambition: it is the very organizational and operational structure of the CNT. So much is this the case that some theorists have purported to divine a foretaste of the functioning of the society of the future in the very manner in which the unions operate and reach and implement their decisions.
That functioning proceeds like this. The unions constitute autonomous units, linked to the ensemble of the Confederation only by the accords of a general nature adopted at national congresses, whether regular or extraordinary. Apart from this commitment, the unions, right up to their technical sections, are free to reach any decision which is not detrimental to the organisation as a whole. There are no exceptions to this principle and it can be stated that it is the unions which decide and directly regulate the guidelines of the Confederation.
At all times, the basis for any local, regional, or national decision is the general assembly of the union, where every member has the right to attend, raise and discuss issues, and vote on proposals. Resolutions are adopted by majority vote attenuated by proportional representation.
Extraordinary congresses are held on the suggestion of the assembled unions. Even the agenda is devised by the assemblies where the items on the agenda are debated and delegates appointed as the executors of their collective will. This federalist procedure, operating from the bottom up, constitutes a precaution against any possible authoritarian degeneration in the representative committees." -- THE CNT IN THE SPANISH REVOLUTION by Jose Peirats.
The naysayers could note the last line about preventing a ruling elite from forming. This format applies to regional, national and global organizing. Yet there's a consensus on these boards that global organizing inevitably entails a global oligarchy.