I mean both parties were wrong.

I think a big reason SE went after Arthurs is really the name dropping. You gotta remember this is recently after the TEA death threats were Yoshi-P had to actually vouch for a team that they did something legitimate. When a streamer drops a name down and hundreds of people are watching that can lead to a bunch of flaming and I'm sure SE wanted to avoid that at all being an issue. The active parsing(and in turn DPS shaming) probably didn't help since they try to keep the idea of parsing on a "We know, don't mess it up" kind of deal.

HOWEVER a ban I don't feel is needed, and instead at highest just be given a warning. A 10 day ban especially for an active streamer playing the game is too much, especially when they're big like Arthurs. That's gonna cause a domino effect of other players throwing in their two cents and threads like this popping up. If you just tell someone they did something wrong in a GM grotto it should be enough of an idea of "Well I don't want to come back here".

I'd like to note this is one of the few cases of a GM report where evidence was actually supplied and wasn't a vague statement. If I can commend anything it's the fact a GM told what exactly it was that got them banned. Instead of the stuff we normally see where you probably have an idea of what was said, but others who want to take part in conversation need to ask.