Why would someone ever even contemplate bringing back a Manager that you sacked yourself half a decade ago, amid massive fan protests for being absolutely woeful and unable to defend, when you have just sacked an ex kopite that none of your supporters wanted but you ignored, who was worse than woeful putting you in a relegation battle and whilst being fully aware that there will again be massive amount of supporters don't want said Manager back.
Answer: Because your name is Farhad Moshiri.
Nuff said.