I wouldn’t say she purposefully lying. She just likes that paycheck too much to actually do any research on her own for the facts of the matter.
She reads from out of a notebook that has all the approved answers for probable questions already provided for her. And if it doesn’t have an answer for her to parrot, she always uses one of two or three standard ‘boilerplate’ deferrals she’s memorized.

FACT CHECK: WH Press Sec. Falsely Claims ‘Assault Weapons’ Ban Reduced Mass Shootings

CLAIM: White house press secretary Karine Jean-Pierre claimed the result of the 1994-2004 “assault weapons” ban was that “mass shootings went down.”

VERDICT: False.

Jean-Pierre opened Tuesday’s press conference by talking about the mass shootings that have been occurring in California, the state that has more gun control than any other state in the Union.

Ironically, one of California’s gun controls is an “assault weapons” ban.

Nevertheless, Jean-Pierre pushed for an “assault weapons” ban at the federal level, saying, “The last time we had an ‘assault weapons’ ban on the books, thanks to the President and Sen. Dianne Feinstein’s (D-CA) leadership, mass shootings actually went down.”

Jean-Pierre’s claim is 180 degrees out of sync with the information discovered and published by the Department of Justice’s National Institute of Justice (NIJ).

Breitbart News reported the NIJ’s findings, which were originally published just as the “assault weapons” ban was coming to an end. The NIJ made clear that the ban could not be credited with any reduction in crime.

The Washington Times quoted University of Pennsylvania professor Christopher Koper, author of the NIJ report, saying, “We cannot clearly credit the ban with any of the nation’s recent drop in gun violence. And, indeed, there has been no discernible reduction in the lethality and injuriousness of gun violence.”

The NIJ report continued, “The ban’s effects on gun violence are likely to be small at best and perhaps too small for reliable measurement.” It put matters into perspective by pointing out that “assault weapons” were “rarely used in gun crimes even before the ban.”

Breitbart News noted on January 18, 2013, that “’assault weapons’ were tied to less than .012 per cent of overall deaths in America in recent years (2011)”. This point is poignant, in light of the NIJ report showing “assault weapons” were “rarely used” in crime to begin with. The guns are bulky and difficult to conceal, making them a bad choice for criminals seeking to avoid detection.

Also, the January 21 Monterey Park attacker used a pistol, and NBC Bay Area’s Christine Ni noted that the January 23 Half Moon Bay attacker appears to have used a handgun as well.

Jean-Pierre’s claim that the 1994-2004 “assault weapons” ban reduced mass shootings does not square with the Department of Justice’s NIJ report.