Thats not what would have caused it. You won't see the text that did.
If you note the text where it shows 'omfg', its still in the text box, that comment hasn't been submitted so thats not what would have triggered the warning.The server doesn't warn you for something that hasn't yet been submitted into the main chatting area.
The server warns first, if the warning is ignored it will then mute.
The offensive text is auto hidden from member view so the screenshot above wouldn't show you what the text was that triggered the warning sorry.
Any explanation?