It's my understanding that, at their height, IS derived much of their revenue from captured oil assets. Note that I'm specifically not making the claim that all middle eastern oil revenue is tied to some terror group, but I'm pretty sure some of it is.

Please do correct me if I am wrong.

That seems like a very specific and comparatively small time period that doesn't really stack up to the attempted scale of claiming that a considerable portion of revenue is used to destabilize middle east states.

It gave them plenty of funds for sure (and only for a limited time) but saying it's a significant enough portion to the point of lending credence to the claim being discussed? I have trouble buying that without a source.

That ISIS got funding from oil is not controversial that I’m aware of. The Independent did a lot of coverage of it at one stage. I’m sure they aren’t the only group too. Depending on your politics, the Kurds make money from oil too, but they are a state waiting to exist in my view.