Thread Locked? Why?

Hummm... I'm not sure if this is the best place to ask this, but I've looked for a way to ask a community manager directly and couldn't find.

My thread called "On the "WoW, Dungeons are Hard" post" was just locked.

I've runed through the forum rules, and I don't think we made any mistakes. The conversation was being held in a high tone, there were no frowned upon actions like necroing or anything like it.

The thread was locked and there is no blue post explaining why. I'm a little confused.

Thanks in advance for any feedback.