Word(s) for the attitude of expecting others to believe the same things one does
Solution 1:
Presumptuousness is a reasonably close match that would work in many related contexts, though a hypernym. The adjective is defined at YourDictionary:
presumptuous: too bold or forward; taking too much for granted; showing overconfidence, arrogance, or effrontery.
Merriam-Webster has:
presumptuous: overstepping due bounds (as of propriety or courtesy): taking liberties
There are already threads covering 'unwilling to change' / 'hidebound'.
Solution 2:
projection - the attribution of one's own ideas, feelings, or attitudes to other people or to objects
This isn't it entirely. I have not had luck finding a term for the logical fallacy of building an argument upon projection of one's own attitudes to others. Maybe projection combined with argumentum ad populum.