The initial infraction seemed way over the top in my eyes. His comment to Mo was a bit cheeky, but there is far worse stuff posted on here, day in and day out. The infraction for his comments to the moderator was overkill.
However, he was asking for a ban by starting a topic calling said moderator a prick, so it swings both ways.
Is it a permanent ban, or just a week? If it's permanent, then I think that's a big loss of technical knowledge that the forum didn't need.