Word(s) describing person in "Elephant has tail, elephant has trunk" scenario
A survey shows there is a shortage of women who are software developers. Sarah replies to it saying the reason is because women feel intimidated by the men to women ratio in the workplace.
John replies saying a reason for the shortage could be that women generally prefer roles where they interact with other people as well as they prefer a work-life balance.
Sarah tells John he is statement is incorrect, he doesn't know what he is talking about and she is correct.
Both Sarah and John are correct How would you with a single/ two words describe her or her stance of only believing/focus on one answer, her answer, when there are multiple answers.
Another example:
Pete says an elephant has a trunk. Dave says an elephant has tusks. Pete says Dave is incorrect but he is correct. Both are correct. Which single/ two words would convey that Pete's view is correct but at the same time incorrect by discounting Dave's view.
This could be a case of fallacy of the single cause or some other logical fallacy.
fallacy of the single cause
Dictionary Definition:- The fallacy of the single cause, also known as complex cause, causal oversimplification, causal reductionism, and reduction fallacy,[1] is a fallacy of questionable cause that occurs when it is assumed that there is a single, simple cause of an outcome when in reality it may have been caused by a number of only jointly sufficient causes.
The posted scenarios are examples of people with a blinkered outlook. This implies that their perception of the world is highly constrained by their prejudices and limited world view.
The facts that a person with a blinkered outlook recognises are usually true but, because they refuse to recognise other facts and world views, their interpretation of those facts is often very wide of the mark.
The phrase is a metaphor taken from the idea of a horse having 'blinkers' fitted so that it can only see ahead to reduce the chances of its becoming startled and bolting.