Disclaimer: I'm not saying this applies in general. This is only my own experience.
I had a bad time with the 3 office narcs because they directly impacted my work. Colleagues who were not impacted found them to be perfectly pleasant. Colleagues who were love-bombed thought they were lovely people. And some colleagues objectively knew they were liars, unreliable and losers, but still liked them because subjectively they appeared to be nice or they just kept giving the narcs the benefit of the doubt.
IMO, most people don't want to think the worst of anyone. They find the levels to which narcs descend to be unbelievable. So, unless you get personally backstabbed, you prefer to think that there may be a plausible reason for what they are doing, whether it be foolishness or idiocy. It's only when you become their victim that you look into self-preservation or, as Piers seems to be doing, counter-attack.