When intelligence analysts keep reading and hearing the "typical" threats that right wing extremists are known for, day after day, week after week, they can become (I previously used the word "numb") "inured" to what might happen if these threats become operationalized.
I do think that the lack of preparedness for the Capitol riot is based on an intelligence failure and the failure of law enforcement to act on the intelligence that was provided to them. Sometimes people just don't act on the information they are provided with. We make deadly assumptions that provide an excuse for our unwillingness to take action. Some have called the above similar to 9/11's "lack of imagination."
The word "inure" is defined as "to accustom (someone) to something, especially something unpleasant." We all know blowhards of different types. They threaten to quit their job, move to Hawaii, dig a bomb shelter, punch someone in the face if he/she says something again. Then, lo and behold, they up and do what they have been talking about forever. We then seem "surprised" that this finally happened.
In the intelligence business and those who get warnings from intelligence experts, the duty is to become prepared, not to dismiss threats as being just idle talk.
