Michael Horowitz’s report on the Clinton e-mail investigation is chock full of “whoa” moments, but it’s best to keep in mind that his goal as Justice Department inspector general is to try to re-establish standards for both Justice and the FBI — not to actually say whether the Clinton probe was done properly.

Ex-FBI chief Jim Comey writes in The New York Times that the report “resoundingly demonstrates that there was no prosecutable case against Mrs. Clinton, as we had concluded.” Not so: It says the decisions that led to that conclusion were all, individually, within the bounds of department guidelines.

And there are bombshells along the way, like the fact that Comey himself sometimes used his personal e-mail to conduct (unclassified) FBI business. And that top FBI agent Peter Strzok actually e-mailed documents from the Anthony Weiner investigation to his own private account.

Indeed, Horowitz seems most frustrated by the Weiner angle — in particular, by the fact that the FBI’s top ranks waited nearly a month before acting on word from New York that the feds there had found Clinton e-mails on the disgraced ex-congressman’s laptop.

He finds all their explanations for the delay “unpersuasive” but couldn’t “identify a consistent or persuasive explanation for the FBI’s failure to act.”

He does flag the reluctance of Strzok to turn his own attention back to Clinton, from the investigation of possible Team Trump collusion with Russia — which has to be judged in the context of Strzok’s “We’ll stop it” text about the possibility of a Trump presidency.

Comey, meanwhile, told the IG that he’s not even sure he knew in October 2016 that Weiner was married to Huma Abedin. Really? Quite apart from what he should have known about a central figure in the Clinton probe, Abedin was prominently by Weiner’s side during two scandals that made national news for weeks on end.

Horowitz faults Comey as “insubordinate” for both his June announcement that he didn’t think Clinton should be charged (even as he slammed her conduct) and the late October announcement that he was re-opening the investigation.

Maybe Comey was wrong to “speak out,” as he puts it. But maybe he should have made bigger waves earlier on.

The FBI was furious over President Barack Obama’s public statements clearing Clinton long before the investigation was done. Many agents seriously questioned decisions by their Obama-appointed overseers at Justice in the Clinton probe. And investigators knew that Obama himself was at least slightly implicated, thanks to his e-mails with Clinton.

Plus, Comey chafed at Attorney General Loretta Lynch’s directive to call the investigation a “matter,” and was outraged by news of her tarmac meeting with Bill Clinton.

Distrusting his political overseers, Comey took matters into his own hands.

Perhaps someday he’ll explain why he never seriously considered calling for a special counsel to cut the politicians out of it all.