Here's the real facts (as opposed to so-called alternative facts ie made up lies):
1)US Attorneys serve at the pleasure of the President. Traditionally a new President (when the political party changes) do ask for resignations and replace all, or nearly all US Attorneys. For example, Obama left only one GOP US Attorney on for Obama's entire eight years.
2) That said, generally incoming Presidents do the replacement in an orderly fashion, having most if not all current US Attorneys stay until the end of their four year term or until a replacement is nominated and confirmed by the Senate. Sessions said in his confirmation hearing testimony this was his intention, not the sort of mass firing/resignation he did last week-with no replacements even nominated, much less confirmed.
3) After the election Bharara had personal conversations with both Trump and Sessions and both expressly promised him he would not be replaced.
4) Baharara has a reputation on aggressively going after political corruption, no matter which party involved.
5) Trump Tower is within the jurisdiction where Bharara served.
6) According to Baharara, he refused to resign and was fired by Sessions yesterday.
My conclusions:
A) Typical bull in china shop behavior from Trump- having 46 nominees coming to the Senate at once-all of which will probably be nominated late and with inadequate vetting (witness General Flynn). Trump is probably going to nominate more than a fair number of hacks and wackos.
B) Odds are Trump was scared of Bharara coming after him.
C) On the positive side, Bharara is now available to serve as special prosecutor for whichever Trump scandal reaches that stage-but it is highly unlikely the GOP would consent to a real bulldog in that position.