GMs don't tell you the exact incident because it could involve a witch hunt. Even though most situations it'll likely be apparent where the report occurred. Just that some people play the game almost too much that their untamed sarcasm or toxicity happens too regularly they won't even realize they are a problem until they are reported. So it's probably a mixture of both.

Basically if you are making people uncomfortable in the game, you should stop, like yesterday. The last ToS revision gives GMs more leeway for just being an overall unpleasant person in a party.