Sexual Orientation. Straight? Bisexual? Gay?

Why is there such a huge fuss about ones orientation?
Why is it such a big deal? I don't think it should be.
What you are is what you are right? and no one can change that.
So why not be able to get married to the same sex?
In my opinion love is love it's meant for anyone whether you're a bird or just a small little ant. The thing that really gets me about this subject is that teenagers these days are going from straight to bisexual because it's the new "trend" and I bet if you payed close attention you would definitely see that. If you're straight you're straight if you're gay you're gay but when you change your sexual orientation because everyone is doing it it's just not right.
You could end up hurting someone who loves you because you realize you really never liked the same sex. Am I right? Trends these days have gotten people into huge trouble like well when it seemed like everyone in your high school was cutting them selves or doing drugs.
But only you can tell who you really are. Are you emo? Are you a stoner? Are you GAY? But besides high school but in the real world why do people need to freak about something like "OMG so and so doesn't believe in gay rights" or whatever.
Everyone's entitled to there own opinions right? Well what I want to know is. What do you guys think about this? Do you agree with me? Do you disagree? Does any of this ever cross your mind? Leave comments and share your opinions.