I think this is the cultural difference between East Asia and South Asia. Although Vietnam is a Southeast Asian country, its culture belongs to the East Asian Confucian cultural circle.
East Asian countries usually do not confuse political and economic issues. For example, China and Japan have too many contradictions and hatred between the two countries, but China is still Japan's largest trading partner. If two countries have major natural disasters, the other country must be the first to provide assistance.
However, South Asian countries always like to tie political issues with economic issues, which is not just India's unique habit. The same is true of Pakistan, for example. I saw some Pakistanis even refuse assistance from India a few days ago.