That is a very weak argument, there is no logically sound reasoning provided at all.
All aircraft are trade-offs, SU-30 is a heavy aircraft that provides the large fuel storage capacity needed to cover India's large landmass. But that does come at the cost of increasing it's radar cross-section significantly. Though the MiG-29 has a similar shape, it is much smaller than the SU-27 family, and hence provides lesser range and RCS. You cannot assume that "MKI" is some deadly little bird that no-one else can ever beat. Even Africans have had SU-30s and MiG-29s battling it out with mercenary/hired VVS pilots on both sides.
The JF-17 carries the latest modernization of the SD-10 family, known as the SD-10B, it has been considered a rough equal to AIM-120C5(slightly older AMRAAM) even by western sources. And China has been investing alot in this sector, and since SD-10B is it's main active-radar missile(on the J-10, J-20, J-11 as well), this missile would likely see alot of development and improvements in the future as well. So, an SU-30 would not have a walk in the park with this on it's tail, the large RCS would make it difficult to shake the missile off, as the aircraft's RCS would be relatively easy to detect.