And so what? So what if you happen to be gay or bisexual? What I find a big problem with is when they try to make someone that is gay into "straight", usually by setting them up with an opposite sex spouse that is totally incompatible with them. They might be totally unattracted to the person picked out for them, resulting in a bad marriage.
And yes, it might be a passing phase or a negative spell on them. Someone that is naturally straight could fall into a spell that could artificially make them gay--and, when that spell is broken, they will be straight. Usually, however, it is neither. Someone can be part-gay and could fall into what appears to be a phase when in fact they are bisexual. I see nothing wrong with that--better they be in a gay relationship they are compatible with, and fits their nature, than in a "straight" relationship they are not suited for and does not fit them.