In a sense it's true; the folks who wanted to violently revolt against the UK government were, in fact, UK citizens. Similarly, the folks who want to topple the house of Saud and impose their own government on Saudi Arabia are mostly Saudi citizens.
But I think it's a stretch to call that relationship "creator" and "sponsor". The UK government, as an organization, is staunchly opposed to the IRA. And similarly for the Saudi government.
At the moment ISIS does promote regime change in Saudi Arabia, so the regime there really don't like them related to that, but the former history is very different.
They also don't complain to ISIS' application of Sharia (punishments, like decapitations and outlawing homosexuals and atheists) as they are anyway prescribed by the same Sharia understanding, in big part common to Saudis and ISIS. They also don't condemn fighting against Shias, as both consider them "unbelievers" who are to be fought and killed.
Assad is also Alawite, also the enemy of both ISIS and Saudis.
Edit: I see you again try to "prove by" (for me false) "analogy with IRA" in your following reply. Please just stay on topic to ISIS. You can't prove anything, at least to me, by avoiding to discuss the relevant facts of the relevant topic.
If you are unfamiliar with the reducto ad absurdum argument, you can familiarize yourself with it here: https://en.wikipedia.org/wiki/Reductio_ad_absurdum
At the moment ISIS does promote regime change in Saudi Arabia, so the regime there really don't like them related to that, but the former history is very different.
Yes, and similarly if the IRA jailed rapists and allowed Christianity in territory they controlled, I doubt the UK would object much to that.
The fact that two European groups have cultural similarities doesn't mean that one sponsors the other. The same is true for two middle eastern groups.
Fundamentally, I bring up the IRA because I'm trying to explain by analogy to something more familiar. You seem to be viewing all middle eastern organizations as being somehow monolithic and identical simply because they are more similar to each other than they are to the west. But that's simply a fallacy.
