The majority of people are short-sighted and/or greedy. The only way to make change is through action such as this. Or violence. But let’s try this first.
India is not by any sensible measure a "major offender". They do have the third highest total emissions but that is because they have the largest or second largest population. Their per capita emissions are half of Switzerland's.
And yes, per capita is a far better measure than per country unless you can make a case that the people of some countries have some sort of natural or divine right to live a higher CO2 lifestyle.
The women who filed the suit are Swiss.
I'm all for suing other nations as well, but we (wealthy western nations) need to get our ducks in a row first. No point suing Poland about coal use while we (USA) also burn coal.
Pointing to the inaction of other countries as an excuse for one's own inaction is a weak argument. Good luck suing Russia. (They were actually a member of the Council of Europe until 2022, so this decision would have applied to them...)
But then this feels like suing somebody for emptying his ashtray in a canal where 100 meter further a factory is discharging chemical waste. Good luck suing the factory.