https://www.npr.org/2017/10/27/560308997/irs-apologizes-for-...
Spoiler: both liberal and conservative groups were subject to extra scrutiny via keyword triggers, but only conservative groups got a settlement for whatever reason only Trump knows. Trump was smart enough not to let it go to court (lest any facts get argued for real).
For the actions committed under the previous liberal administration.
Trump becomes president: see, I told you, the IRS under Obama was corrupt! Let’s settle everything and withdraw all criminal charges (because you can’t just say people are guilty) so a judge/jury doesn’t actually determine anything.
But maybe this is valid under Trump supporter logic, I guess.