I don't have a bone in this race, but if someone has deliberately hidden their identity online, knowingly disclosing that is malicious, regardless of any other morality involved.

Consider people who have their public persona very deliberately obfuscated, like Banksy, or Chuck Tingle - it's very intentional that both of them do not disclose that, and if you found out either of their legal names, and disclosed it publicly, it would be with deliberate intent to subvert them.

Or consider if someone posted online they had a beer, and they lived somewhere that considered that an egregious crime even if they did it somewhere that it was legal. If you deliberately released proof that the person posting "I had a beer" was this person, it would have malicious intent, regardless of how you feel about the morality of beer.