Mental illness is hard to diagnose. According to the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5), a metal disorder must affect so much more than a person’s behavior. It affects their daily life, their ability to distinguish reality vs dreams, and how people treat themselves. It also must happen consistently for several months.
For people with Histrionic personality disorder, it would be unwise to assign them a diagnosis so quickly and easily. Being the center of attention is related to extroversion and having fun. It’s different for someone who can’t function without it. People with Histrionic personality disorder will even go as far as threatening suicide to gain sympathy from others.
Because mental illness is such a complex condition, it would be unwise to assume homosexuality is associated with it. In most cases, gay people are straight for many years before they realize that they’re homosexual. If they’ve been able to function for years without homosexuality, then homosexuality can’t possibly be a mental disorder. Instead, embracing one’s one sexuality has brought peace and comfort in knowing who they truly are.