Do you know why, as someone with clinical depression, I identify with those who are Mormon and gay?  Because a similar misunderstanding exists and similar excuses are made.  Depressed people don't deal with nearly as much stuff as gay people do, but I do see similarities, such as:

Both groups are living contrary to God's law.

Depressed people are obviously still living with some sin they haven't repented of, or they wouldn't be so sad!  They are probably not reading their scriptures, praying, going to church, paying tithing, fulfilling their callings, etc. enough!  Being happy all the time means you're being righteous all the time!

Gay people are just plain wrong.  They should stop liking the same gender and switch to liking the other one.  Duh.

They could be cured if they just have enough faith.

If you still have depression, you must have not had enough faith so far to be healed.  It's all up to you.  This is not an actual "medical" disease that needs to run its course at all!  You're just sad!  Really sad, that is, but still–it's just an emotional problem.  See above for why you are so sad.

Homosexuality is a temptation nigh unto a disease.  Have faith and you will be cured.  If you haven't been cured already, you must not want to be badly enough.  Even though it is a temptation, just ignore Paul's bit about having a thorn in his side that was never taken away even though he prayed for it.  Paul obviously wasn't faithful enough!  Yes he was an apostle, but. . . .let's change the subject.