That's absolutely true - some things are easier to change than others. I like your sushi example; it's easy for most people to "try something new" when the experience feels disposable and non-threatening to someone's current worldview.
It is much much harder to ask someone to be open to a new way of seeing life, especially in the areas you mentioned. Pick your favorite controversial political topic - a prime example of how difficult it is to get people to open up.
It is much much harder to ask someone to be open to a new way of seeing life, especially in the areas you mentioned. Pick your favorite controversial political topic - a prime example of how difficult it is to get people to open up.