That's the convenient part. There is no shared border or waters; there is no conflicting interests to make a compromise over on the paper. They are not in a military alliance. There isn't really anything to uphold. And the pivot to India started only with Sino-Soviet split.
Russia has a strong historical track record of honoring its treaties and commitments with India and many other Asian nations.
Also, one could point at the US and apply your statement more accurately.