Not necessarily true. Sexual preference doesn't appear on death certificates.
That's because there is no such thing as sexual preference (as an immutable characteristic) there is only sexual behavior.
Your statement is the proof that 'homosexuality' is a chosen behavior. How can you tell that one corpse was 'gay' while another one wasn't? You can't.
Homosexuality is a mental disease caused by trauma and is 100 percent curable for those who want to be cured. It is not an orientation or a characteristic.