VIC Is that legal to post a group chat history in my case?

[Chris A1AA]

Hi, Is that legal to post a blog online of a group chat conversation history?

1. The group chat consists of 450+ people. Anyone in this group can invite any others to join the group without the group manager's permission, and most of the people in this group are strangers to each other.
2. The group chat history will permanently be saved, and can not be deleted once it has been sent over two minutes. The group manager also can not delete any history.
3. I involved in this conversation with another people(Let’s call him A).
4. I want to post the conversation history without the permission of A. He insisted that the problem we have of an issue was on me, and trying to persuade it was my fault. And I am feeling really bad and hurt. I want public help.
5. I blur all personal information(including nick/user name) and only left with the conversation. No one could identify any personal information through the screenshot of conversation history.
6. He is threatening me if I post these conversations(original history, without editing of original conversation), he will sue me.

In such a case, I don't think it is illegal to post online since it is not even a private conversation.

Secondly, If I am posting with their nickname and profile photo(means their name in the chat), but without any personal information such as phone number, address and etc, will that be legal?

Any legal regulation/laws can provide to me?

Thanks to you all for great help.