There are a variety of scenarios possible:
1. The data is purposely allowed to be transmitted by IN intelligence to put the chinese off track or confounded at worst. (just like US let go neutron bomb "designs" to hacking so that the "researchers" waste much effort and money trying to chase and pursue in the wrong direction).
2. Counter intelligence / counter hacking is at a higher level that no one knows if it exists. How many "achievements" of RAW do we get to know ... and what we get to know, they are actually a bad showing that RAW failed to keep it a secret.
It is not an that ISI activities or in this case chinese govt hacking become publicly known. Both point to a significant lower level of capabilities, that they can prevent detection.
3. Nothing has actually happened, such that even no attempt was made .. but what's harm in putting out public news to paint the chinese black. It makes the world cautios .. or even over cautious
laugh
, or perhaps for commercial reasons.
4. And lastly, if chinese are indeed involved.. they have surely fallen to so low a level that they need help from Indian nuclear submarine technology to spruce up their own. And then do we need to worry about such an opponent?
The least, if does tells us that chinese could be quite scared of IN moves into SCS in the coming decade. Helps us use their fear as a political chip .... now that their hacking attempts are out in the open.