Because India has no choice.
Firstly, India is unable to purchase fighter jets of the Chinese system.
Secondly, India cannot afford the political conditions attached to American fighter jets.
Thirdly, the quality of Russian fighter jets is poor and they cannot be delivered on time.
So India actually only has three options: Rafale, EF2000, and Jas-39.
EF2000, as it is a multinational cooperative production, has always had slow political decision-making, and upgrading power is decentralized and difficult. External sales have always been difficult. It is even less likely to provide India with technology and production lines.
Jas-39 is a light fighter jet, and for Tejas, India will not consider a light fighter jet. And the key subsystems of Jas-39 (F414, radar, electronic warfare system, APU, etc.) are all controlled by third country technology, making it difficult for India to guarantee that it will not be subject to technology blockade and sanctions in the future.
So India can only choose Rafale. India already has a mature Rafale system, pilot training, logistics, ammunition, and maintenance chain are all very mature. France usually offers very high kickbacks when selling arms, which is suitable for India's national conditions. And it does not come with NATO operational restrictions. It is still a medium multi-purpose fighter jet. It can enable the Indian government to promote India's assembly, fuselage manufacturing, M88 maintenance center, and also shape India's diplomatic image as a "Western high-end fighter jet but not politically hijacked by the United States".