Professor Paul Nelson of Texas A&M University and a fellow of the American Nuclear Society has a theory... and concludes that none of the six are in a position to sit in judgment of India.
Perhaps these states have little need for nuclear technology, either for civilian energy or military deterrence, and therefore simply are not well positioned to understand India's need for either?
The following table contains data possibly relevant to the civil part of this hypothesis.
Per Capita GDP
The second column of this table lists the percentage of electricity generated in the indicated states that is produced by nuclear energy, termed as “nuclear reliance.” Except for Switzerland, these nuclear reliances - including that for India - are all well below the worldwide value of 16%. What possibly accounts for this?
A possibility suggested by the third column is that these countries - all of which have a per capita GDP (denominated on the basis of local purchasing power) at least eight times that of India - can well afford to rely largely or exclusively on alternatives to nuclear energy.
Why is Switzerland such a notable exception, in terms of its nuclear reliance? Perhaps the answer lies in its large reliance on energy imports (56% of energy consumed), along with the high value it has traditionally given self reliance. A degree of the latter is provided by nuclear energy, owing to the 2-3 year lifetime of a typical reactor core, not to mention the potential for stockpiling nuclear fuel. The latter is available (under international safeguards) to most states - but not currently or historically to India.
Is this suggestive of why these states might not particularly identify with India’s desire for civil nuclear energy?
You can read his short analysis here.