Good question. The last sentence answers your question the best way possible........"they refuse to accept that about themselves".
It is called repression: a process by which unacceptable desires, or impulses, are excluded from the consciousness and left to operate in the subconscious, or unconscious mind.
This is a common state that many gay people must live with because of societal and religious condemnation. If one denies what, or who, they truly are this process of repression makes it easier to coexist in a society that does not understand what is happening to them, and that would ostracize them if the truth be known.
But there are prices to pay for such intense suppression of the true self. The constant battle to force the conscious intentional exclusion from consciousness will ultimately destroy the mind and force the person to face who they really are, or commit suicide to keep their secret from the world, and destroys many lives in the process. When there is a spouse and children involved it makes the battle within even more wearisome.
In a society that brags about equal rights, birth rights, and civility, no person should ever have to fight this battle by themselves. We are what we are, and it is time that the ignorance be silenced so every person can pursue their own given path in life.