Check the report, Trump specifically asked for his resignation and he was given. Then Trump relented. The question should be, why did he change his mind?
To think Sessions would have resigned and gone timidly into the night is naive
From the article:
He then rounded on Mr Sessions, calling him an "idiot" and demanding his resignation. An "ashen and emotional" Mr Sessions duly did so.
But in the hours that followed tempers cooled and Mr Trump heeded the advice from other senior aides that losing the Attorney General would intensify the chaos in the administration.
Despite feeling humiliated Mr Sessions, who is one of the most conservative members of the administration, remained in place.
Looking at Session's actions, he has lied under oath for the administration, he has enacted racist policies under the administration, he has been publicly berated, privately humiliated (see above) he has been painted as a scapegoat and he has meekly offered his resignation.
ONE time he releases a statement that his office won't be "improperly influenced" and all of a sudden he knows where all the bodies are buried and is about to bun down di system? Unless I am overlooking something (and please let me know if I am), there are no other instances of Sessions showing that he has a spine or that he is about the action.
His conservative views appear to be the driving force in his legacy, not his personal ego, so sullying his name is not going to cause him to lash out at the GOP or he would've done so ages ago when he became a public punching back.
I think you need to reel in your expectations in terms of the human range of emotion. Sessions isn't some seedy, 2nd rate Saul Goodman or some drunken energy adviser at a bar (George P.). The idea that everyone is looking to take down the administration in a vengeful response is naive and overly-optimistic. There are plenty of people who have been fired who have not chosen to take down the administration. The fact is, Sessions is uniquely tied into the investigation, so his firing has additional layers of meaning. This is why he is still on the admin