story
Can you please elaborate? I don't know enough of the details to understand the link you're making.
> The existence of market failure is no position. Just for the fact that there is market failure does not have any implication on what to do about it.
The first sentence is incorrect, and is not implied by the second sentence, which is correct. The 'position' is that, in order to have an efficient market, one should not do things that cause market failure. It is a negative position rather than a positive one (DON'T do X rather than DO X), but it is still a position. It informs you about what sort of things you shouldn't do if you want a market to operate efficiently.
> That is simply something that is often assert because it makes for good propaganda
Saying that collusion can lead to market failure, and thus must be proscribed if one wishes to have an efficient market, is not propaganda. It is the kind of thing that must be said, seemingly repeatedly, to illustrate the point that markets are not a magical solution to the allocation problem.
The argument you subsequently make, that "we don't know better", is both completely standard and completely wrong. We may well not know better than an efficient market - I'm not sure but it seems very reasonable. However, moving from that to suggest that imposing controls such as anti-collusion regulations (along with a whole host of other measures to avoid market failure), is unnecessary, is unsubstantiated.
If you examine your own argument, it is based by your own admission on an assertion. The foundation for why one might think that what you are saying is true (market theory) explicitly lays out the assumptions required for it to work, and you ignore these on a purely ideological basis.