This is a very interesting story, I think it would not be hard to check the flight record and even ask UA for comments, if the OP can provide the flight number and date as well as something clearer than "Bombay to India".
We can't pass judgement on the FAs without knowing the full story and knowing the legislation governing strikes in the US (at least I don't know it). Strike is a right. Someone would have to see whether the strike was in conformity with legislation, and what their trade union thinks about it.
Once I was in Italy and the train stopped at a mid-way station as there was a strike. The train people were so kind to drive me and my former girlfriend to another town to help us make our way. They were very apologetic and took the opportunity to explain why they were striking. They were within their full right to strike, even though it really f--ed up our plan, but still, it was an interesting experience and I don't blame them for striking within their right.
Airline staff get paid far too little in most countries. It's good to travel the world, have a nice lifestyle, and that's why it attracts good people and you have so many good people in the airline business. But the salary is not enough... So I don't blame them for striking especially if they do it according to the rules (which may or may not have been the case), although it's extremely annoying for passengers -- just like volcanic ash or terrorism threats are also annoying.