I 'get' what you are saying and I agree to some extent. The classic joke for psychiatry used to be 'how do you cure schizophrenia? By crossing the Atlantic'! Meaning that British psychiatrists had a different checklist to American and therefore mental illness is subjective rather than a 'fact'.
The only difference I would make is that people with bipolar can/may experience relief from symptoms if medicated or coping strategies - being active, relaxation techniques, etc. depending on individual experience of those symptoms.
Homosexuality is not made different by any of these because it is not a 'condition' to be treated in the first place.
That said, I wish we would accept psychological and mental illness as a part of life and not stigmatise and be afraid of it.