If it was a single post, an infraction would have sufficed. Flaming/Raging in General, is generally enforced more strictly than in other forums.
No matter who you were flaming, it can't be done outside the flame section. The rules state a ban for flaming outside of the flaming section.
Which is what was done. Would have moved it to flame but it really wasn't a flame thread with any real reason. It was just him "calling you out" and really that can be done elsewhere. Also considering since the posts were leading basically to bullshit spam.
You were both banned for basically the same reasons.