The fact is, something like 10% of the bitcoin network jumped over to mine it. I don't think they were expecting that, and I don't think any coin could support that much right away without any hiccups. (Have any other alts had that much power at launch and managed fine?)
The last 2 hard-forks had nothing to do with mining unlike what they misled their base to believe. They simply used the wrong peercoin fork by accident during the PoW to PoS transition.