This whole issue kicked off somewhere between 7-9 years ago so my memory is hazy. You need to google Chelsea Manning as it is the leaks from that source which Assange printed. Some showed abuses of power by soldiers but the claim is that the leaks were just a dump of information and some contained information that could have put American soldiers lives at risk. They were not selectively targetted leaks, they were a mass dump.
You would have to trawl through an awful lot of stuff to see who was right in all of this, perhaps some was good to release, some not so, but I think any country that has secret information leaked, some likely to be very sensitive, is obviously going to be very upset. If the information contained details that could threaten the safety of its soldiers, even more so. If someone would like to go through all of the pages then perhaps they can tell us all whether it was safe to leak or not.
You would have to trawl through an awful lot of stuff to see who was right in all of this, perhaps some was good to release, some not so, but I think any country that has secret information leaked, some likely to be very sensitive, is obviously going to be very upset. If the information contained details that could threaten the safety of its soldiers, even more so. If someone would like to go through all of the pages then perhaps they can tell us all whether it was safe to leak or not.