That some action is made right or appropriate by some hypothetical fact or condition is a rhetorical legerdemain. You're going from a hypothetical or conditional to a declarative, from if, to makes.
You also have too many thises so your sentence is like a traffic cop in Rome.
If Saudi Arabia and the US and Israel as its allies are destabilizing
the region by funding and supporting radical groups, why wouldn't
Russia and Iran be justified in countering that move?
If you wanted to use make right in the sense of to justify an action:
Saudi Arabia and the US and Israel as its allies are destabilizing the region by funding and supporting radical groups. Do these concerted efforts to destabilize the region not make it right for Russia and Iran to counter them?
But that rhetorical question is involuted, since you're asking if the concerted efforts themselves justify attempts to counter them. Why cast those concerted efforts as the subject of make? Of course, you're referring to the fact of those concerted efforts, that they are underway, not to those efforts per se.
So you might as well be forthright and pose the question like this:
When Saudi Arabia and the US and Israel as its allies are destabilizing the region by funding and supporting radical groups, are not Russia and Iran justified in countering those concerted efforts?