Frankfurt famously argues that because it ignores the authority of the truth entirely, whereas a liar at least acknowledges that facts matter by trying to hide them. Useful Resources and Analysis

If you are looking for deep dives or critical academic looks into his theory, these papers and resources provide excellent context: On Bullshit

Frankfurt’s most influential contribution is the philosophical distinction between a liar and a "bullshitter":

Is indifferent to the truth . Their goal is not to report facts or even to conceal them, but to produce a specific impression of themselves or to persuade their audience, regardless of whether the information they use is true or false.