I think they're referencing your using an assumed ideological generality/commitment ("liberal") to refer to someone in response to a common albeit somewhat tiresome joke.

It looks a lot like you were trying to be dehumanizing, rather than constructively asking the person a question. Most people understand that asking a question or entering into honest discussion requires some generosity, do it's only human nature that people detected when none or the opposite is given.

You know, that choice, the choice to demean people by ideology - seems to tie into to common fears about Marxist and Socialist systems... That they're authoritarian or would be "once the mask was dropped and they gained any sort of power"

...and that seems to be the appearance you would prefer to perpetuate. You're doing Capitalism's work for free. You're actively reproducing the cultural mindset you've been allocated in its system.