Had nothing to do with wPvP. As I suspected…
https://www.reddit.com/r/wow/comments/a6va7p/comment/ebzmg4w/
Hey Morajin,
First, let me assure you that this action was not taken due to any participation in world PVP. I can understand how the timing of the action could have led you to that conclusion so I want to make sure we’re clear that it was not related. We would not find actions, such as taking over a flight point or quest hub, to be actionable offenses. Players have the option of disabling War Mode or organizing a counter attack with their own faction to retake the area.
What you were suspended for was ongoing targeted harassment of others. We investigated a report we received and were able to verify that, after being placed on ignore, you continued to harass another player through in-game mail using multiple characters on your account. Your messages were not limited to a single person; you harassed other associates of this player with unsolicited mail. We provide a number of tools to allow players to moderate their own social experiences in-game. Bypassing this feature to continue unwanted interactions constitutes disruptive gameplay and will result in account action, including silencing or suspension from the game.
I hope this helps to clarify the reason for this penalty. I suggest that in the future if someone places you on ignore that you do not try to contact them either directly or through their associates.