The source relied on by Steele was presented as conveying damaging information on Trump. When this source was interviewed, he said he had no direct information and was conveying bar talk. He denied telling other details to Steele. This was all known to the Justice Department, but it still asked for warrant renewals from the FISA court without correcting the record or revealing exculpatory information discovered by investigators. That included the failure to tell the court that Page was working with the CIA. Finally, Horowitz found that an FBI lawyer doctored an email to hide the fact that Page was working for us and not the Russians.
Despite this shockingly damning report, much of the media is reporting only that Horowitz did not find it unreasonable to start the investigation, and ignoring a litany of false representations and falsifications of evidence to keep the secret investigation going. Nothing was found to support any of those allegations, and special counsel Robert Mueller also confirmed there was no support for collusion and conspiracy allegations repeated continuously for two years by many experts and members of Congress.
In other words, when the Titanic set sail, there was no reason for it not to. Then there was that fateful iceberg. Like the crew of the Titanic, the FBI knew investigative icebergs floated around its Russia investigation, but not only did it not reduce speed, it actively suppressed the countervailing reports. Despite the many conflicts to its FISA application and renewals, the FBI leadership, including McCabe, plowed ahead into the darkness.