More than likely his complaint was that he couldn't SEE the orange AoE effects underneath the Blizzard II graphic spam, not that you were causing more of them, and he was getting hit by some of them. It probably annoyed him because he wasn't used to having to spot around the massive ice cluster, and might not have been in the mood for new stuff in rank-and-file content.

Sure he could have turned off spell effects, but he shouldn't have had to. Regardless you did what you should have in this particular DF, and that's refrain while still keeping up to your best, and if nothing else at least he gave it a while before he decided he couldn't deal with it.

So no, the tank probably wasn't great, but this went down pretty decently by duty finder standards.