Lois Lerner, IRS official who denied conservatives the same unbiased treatment that was given to liberal groups, who pleaded the 5th under oath, who's laptops and multiple backup systems and tapes were all destroyed before they could be looked at by prosecutors, was just given a get out of jail free card by the current gop doj. And I just learned another good one in this saga. Lois Lerner is a lawyer and former president of the Council on Governmental Ethics Laws
Jeff Sessions has a tough job directing an organization that is filled with leftwing democrat activists. The "career professionals", ie Lerner's friends and fellow activists at DOJ, no doubt made it clear that they were not about to prosecute her for doing something they approved of. Sessions probably feels he has to pick his battles. Of course, all I see is business as usual. Why hasn't the Civil Rights Division filed lawsuits against cities like Berkeley, Sf and Charlottesville that were obviously colluding with anitfa thugs to deny First Amendment rights to demonstrators? Why aren't police departments across the country that have allowed anti-Trump riots being sued and placed under consent decrees? Why haven't we seen any mayors or police chiefs who are actively trying to frustrate immigration law being prosecuted?
Primarily because the Justice Department has broader issues in terms of policy to deal with than what you listed above. For example, it is more important to pursue Justice Department action to override sanctuary city legislation (via withholding federal funds or using court action) than to focus on action against individual towns and mayors that would most likely not be successful and generate negative publicity. In many ways this is what the Justice Department should be doing rather than getting involved in every local situation.