While we are autistic, we are also human in the broader sense. Denial & minimisation can be potent defence mechanisms for many people. And given that we’re brought up in ableist societies, it’s hardly surprising that many of us absorb ableist attitudes, which can be hard to shake off even after diagnosis/realisation.
I struggle with lies & even defensive self deception, so I guess it’s even harder to “get” when the person practising it is autistic.