alt Hacker NewsThe truth is not a defense against libel laws in all countries. Depending on where this is the poster could be out a lot of money just for naming names. As such not naming names is the safe answer.
Even in the US where the truth is a defense, you still can be out a lot of lawyer fees because you can be sued for things you say and it can cost a lot of hours in court.
The author is located in Italy, where "it's the truth" is not an absolute defense against defamation like you say - basically, here, causing "reputational harm" is actually against the law, even if you are telling the truth. There are a few exceptions like social interest which may apply, but it is a dangerous game to play because you need to prove that to the courts, as opposed to just proving what you wrote is what actually happened.