There was a lot of hated towards DKs as well in Cata from both miss understanding and bad reputation from bad DKs and in WotLK there was a lot of bad DKs then Blizzard changes up DK tanking in Cata and even further divides the difference between a shitty DK and a decent one.
It was sad to see DKs and warriors just dropping group when there was another DK or warrior out of fear of getting kicked, but I have done full solo queue groups with on hard CC in Cata launch heroics including grim batol just fine. Different tactics was required, but was doable.