My favorite adjective to denote such attitudes is blinkered.
ODO:
blinkered
ADJECTIVE
1.1 Having or showing a narrow or limited outlook:
‘a blinkered attitude’
‘I'm sorry that you feel I'm so clearly blinkered and entrenched and
incapable of having a reasoned discussion about it.’
Another word which works is prejudiced.
ODO:
prejudiced
ADJECTIVE
Having or showing a dislike or distrust that is derived from
prejudice; bigoted: ‘prejudiced views’
‘Of course, these beliefs do not reflect reality; they reflect the
prejudiced views of those who hold them.
prejudice
NOUN
1 Preconceived opinion that is not based on reason or actual experience
‘Some prejudices (preconceived opinions of an individual based on
opinions about the many) have names such as racism, sexism, or
ageism.’
Also, intransigent.
ODO:
intransigent
ADJECTIVE
Unwilling or refusing to change one's views or to agree about
something:
‘her father had tried persuasion, but she was
intransigent’