You're right but he still has a point. The fact that Kreml agreed to produce this system outside of Russia is something really remarkable. The parts you've bolded are correct but yet noone knows the real capabilities of Turkey in the field of missile tech. We have got hints of several ongoing (more or less) secret projects but of course nothing's sure respectively signed yet. So, I guess, even Russia is taking a little risk at this point. I have this feeling that this project, if realised, will encourage an important breakthrough in our missile related R&D.
We'll get dozens of modern S400 missiles. You can't make me believe that we won't secretly "look" inside of one of these. What about the radar systems? Having them is good, it's also a kind of political leverage on Russia. Also keep in mind that Russia must be convinced that Turkey won't let NATO touch these systems. We all know they're already working on S500 but still it would help Western scientists a lot to have a profound insight of this system.
All in all, it's a deal I would describe as "acceptable" (= stopgap solution).
@Combat-Master
I have a question regarding the Yildirim missiles. Did we purchase blueprints or something like that or did we RE the missiles?