It sounds to me like the youth leader doesn't know squat about human sexuality, and certainly nothing about homo/bisexuality. Are those gay men who stayed with and cared for partners dying of AIDS "blinded by Satan?" Are the many LGBT persons throughout history who have given us works of art, literature, and made other contributions blinded by Satan? Are people like Judy Shepard, who watched her son die because two men beat his head in, and now speaks publicly about erasing hatred towards those who are different blinded by Satan? Are the LGBT organists, pastors, theologians, worship leaders and others who have served their churches and ministered to people just as faithfully as anyone else also blinded by Satan?
Being gay/bi/lesbian is about who and how we love. Is love of Satan?
Sounds like you handled the situation well. Good luck in future conversations!
"And though I may not know the answers, I can finally say I am free. And if the questions led me here, then I am who I was born to be." --Susan Boyle
"If all fools could fly, the sun would be eclipsed forever." --Dutch proverb