I received your PM report.
The person who sent you a PM was responding to a Pit thread, and responded with a personal insult, which would have been acceptable in the Pit.
This is a reminder to all that, even if you are discussing something from the Pit, any PM sent must conform to non-Pit rules. Personal insults are only permitted in the Pit. They are not permitted anywhere else, including in PMs.
From the FAQ: