Personally I don't blame Parish for this decision. Their form has been apocalyptic, and they were rightly worried about the direction of travel. I understand the argument that he should have been given a couple of games against the bottom teams, but what happens if they lose them? Surely you then look back and think that the decision not to sack him was beyond stupid.
Let's flip that around - how many people don't believe that our failure to sack Lampard after the Bournemouth games was a mistake? We allowed him a few more games against the dross and we lost them, which (along with not signing a striker over the two transfer windows) may end up costing us our place in the division.
Selfishly, I'd rather they had kept Vieira as they looked like they were sleepwalking towards a massive scrap and that would have made our job a little easier