I can understand why some people are upset.
While coin mining is indeed a "risk" and nothing is promised. The same goes for the business of owning/operation a pool. It is also a risk... nothing is promised.
It is a little unfair to ask the miners to solely bear the brunt of a mistake made by the pool.
In the end, the coins were absolutely not "owed" to the miners... the coins never truly existed... That doesn't change the fact that the mistake was made by the pool, not the miners. Asking for people to send back coins already withdrawn is tacky at best.
It probably would have been in the best interest of ipominer to "write off" the mistake as a loss and move one.
That would make all the miners feel good towards ipominer instead of a little put off by them.
If the pool can't take a loss like that, then it might be wise to be on top of everything and find issues before they become too big to cover.
I certainly wouldn't like to cover the loss as a pool owner/operator, but I would do it. It's never a good idea to make someone else more responsible for your mistakes than yourself. That starts to harbor feelings of untrust and doubt. Two things I don't want people to feel about my business. Just the way I see it.
My opinion certainly isn't the only one... nor is it any more right or wrong than any other opinion... It is just one opinion among many.