ISIL Antiquities Market "saving artefacts"?

Larry Rothfield (Kaylan's review of the new Metropolitan Museum show) discusses Melik Kaylan's review of the new show at the Metropolitan Museum. He considers it ironic that Kaylan mistakes what endangers museum-worthy artefacts in Mesopotamia for what endangers  Mesopotamian archaeology as a whole.

What is most endangered is not the small number of museum-worthy antiquities like those displayed at the Met. ISIS is implementing a regulated "licit" market in areas under its control, and permitting the international export of artifacts -- a kind of parodic realization of the market structure advocates from the collecting community drawing on John Merryman's work have called for. Those artifacts are safe. What is endangered, rather is the context of the sites out of which they will be snatched or chiseled, and the knowledge of the past that this context holds.

Also it is worth pointing out that what actually finds itself on the market is a small fraction of what the earth holds, artefact hunters discard huge amounts of archaeological evidence which is not so readily collectable, and thus saleable, whether in Islip or Isin.

Is it actually true that it is specifically "ISIS" which is involved in this trade? The actual evidence seems to suggest that is not the case.