The concept of presumptuousness
The concept of 'presumptuous' as in 'arrogantly making assumptions about the beliefs or preferences of another person without regard to the possibility of being wrong'.


The words that fit those descriptions would be 自以为是 (literally 'regard oneself as infallible') or 自作主张 (literally 'presumingly assert/decide'). 自以为是 would work perfectly for translating your paragraph. There is also a colloquial word with similar meaning 想当然 (literally 'assume sth. as a matter of course').

If you consider some similar but different concepts, you'll have more word choices. E.g. prejudice (偏见), stereotype (成见), ignorance (无知/愚昧), etc.