That's a fair point concerning the gradual corruption of Krypton over the years, but the troubles with 'Mr Oz' as a concept lie in the fact that the gap between Dan Jurgens' characterisation of him as a seething sociopath and xenophobe are a very abrupt departure to what we were shown of the character in the last three years. While Oz was always very much a blank canvas as a character I felt like I was reading someone completely different with this issue.
Really though that was just one element... the simple truth to the matter is that nothing made much sense in this issue. There is a complete lack of logic to be seen in anything going on within.
Roll back a few issues to Action Comics #976 where we see Mr Oz watch on as the Kent family come together to alter reality and merge together two fractured timelines, and when you stop to think about it the implication from this scene is that Mr Oz/Jor-el comes from the previous, New-52, universe - after all it is clear that wherever he lives and watches out from it is somewhere outside time and space. So apparently he wasn't affected by the rewriting of reality in that issue's climax to the battle against Mxyzptlk and the revision which Superman's life underwent as a result.
If that logic holds then is it not fair to say that this Jor-el, if you accept it is he, would have to be a product of the Flashpoint/Doctor Manhattan breach that gave us the diluted and broken souls that were the New-52 Superman & Supergirl? And more generally a darker more violent universe?
Either way this is a broken Jor-el. A man taken out of time and driven to the edge of his sanity, lost in soul-withering bitterness and seeing the peoples of earth as a suitable target for some manner of undefined personal vengeance. And yet none of it makes sense, not the unconvincing plotting here in this issue nor Jor's reduction to petty evil spite and terrorism. Why? What is the point? The most gifted scientist and visionary of his generation Jor-el believes that attacking lesser and harmless peoples is a worthy and profitable exercise...?
It lacks any sense of logic. But then so does the issue as a whole.
I would take him as being the PC version of Jor El, who has somehow been broken/corrupted by Manhatten...
I am strill trying to understanding just who was the person that even Mxy seemed to be fearing, Jor El/Manhatten or?
And why does it seem that Time Trapper Prime might still be part of this?