It didn't exonerate the FBI, I agree with that part. It found errors, which doesn't particularly surprise me. I bet any large scale investigation has errors. And yes, we should clean up those errors. But again, the report found no bias or improper motivation in launching the investigation. That hasn't been the mantra of Trump.
By all means fix the errors. I am betting Carter Page isn't the only American to run afoul of FBI procedural errors. On behalf of all Americans, the errors need corrected.
We can acknowledge that the IG report noted legitimate surveillance program issues. However, the flip side is that we have to all also acknowledge that it debunks the conspiracy fever dreams of Trump. Both can be true.