Here is a review from the particle data group of searches for compositeness for quarks and leptons. . It is from 2001 but I suppose that they are not updating it since it gives the basic parameters for their table of limits for quark and lepton compositeness (2015).
In the review the word "confinement" does not appear, as it necessarily would have, if confinement were a necessary and sufficient reason for the elementary nature of the quarks. There is no evidence that quarks are not confined at present. There are theories where quark decays will violate baryon number conservation, thus leading to proton decay, but that is another story not involving confinement.
As the link provided is from twenty years ago, from within another physics subculture, probably it has to do with a particular theoretical proposal that has not emerged in the western story line of quark compositeness. I would trust the western version, as our experimental results are surely valid.
Here is a review of theory on confinement
Quark Confinement: The Hard Problem of Hadron Physics
"Compositeness" is not found within it either. It does speak of :
It is odd to have a complete theory of one of the four well established forces of nature the strong nuclear force and still not have general agreement, after more than thirty years of effort, on how that force really works at long distances.