Reba said:
Yes, I believe that homosexual sex is sinful.
Assuming that you do not believe heterosexual sex is sinful (if you do, I suggest joining the Shakers), you do not believe sex in itself is sinful. Thus, it can be discerned that there is something other than the sexual nature of homosexual sex that you believe to be sinful. What this something is is typically the fact that it is occuring between two people of the same sex, that is, the homosexual nature of the practice. Logic dictates that if you think it is the homosexual nature of homosexual sex that you believe to be sinful, you would believe homosexuality to be sinful.
Sin is defined as "A transgression of a religious or moral law, especially when deliberate." This of course would indicate that sin is entirely dependent on religion. Without religion, the concept of sin would not exist. As religion is for all intents and purposes mythology, that is, fundamentally impossible to prove scientifically but possibly valid ascientifically, regardless of any individual's convictions that a particular religion is "correct", the way in which scripture is interpreted is generally set by the religious scholars and priests. Now, there is a great degree of interpretation to be done. What you read in a holy book might be read entirely differently from someone else. The notion that one will generally interpret something which is ambiguous to fit their personal opinions is well understood to be true in the field of psychology.
Thus, the problem of interpreting anything strikes in the field of linguistic theory. It is impossible to understand exactly what an author meant in a particular writing if the author is no longer living. If the author was alive, you could of course request clarification in order to gain a better understanding. The immediate family may understand a lot also, but we, thousands of years later reading the Bible, are several orders of magnitude removed from the original authors. It follows, then, that we cannot even possibly comprehend the precise meaning of what any particular part of the Bible was intended to mean, as colloquial definitions of words, and indeed the languages at large change at a reasonably fast pace (Compare Old English or even Middle English to Modern English, for example). Additionally, many words that were understood to mean a certain thing in specific contexts are no longer used or have been replaced with less ambiguous vocabulary.
It can be said, thus, that your belief that homosexuality is sinful is not actually grounded in scripture (because if it was, then the knowledge that there is nothing in the Bible stating homosexuality is sinful should logically cause you to disenfranchise yourself with that belief) but instead grounded in your own personal biases and predispositions. You do not actually believe homosexuality is sinful, you believe homsexuality is
wrong, which has an entirely different meaning.
"Wrong" is an adjective which means "Not in conformity with fact or truth; incorrect or erroneous." It follows that if you believe homosexuality to be this way, that you see something fundamentally incorrect with homosexuality. This is the reason you would not support the advancement of freedom for gays and lesbians--you believe their existance to be wrong. You do not actually believe it is sinful, as the nature of sin, by direct correlation to religion, is utterly arbitrary, rather, you believe that it is wrong.
Now, to state the existence of a person is incorrect is to state that for some reason, the person is not a "correct" human. A correct human would logically be one which constitutes the definition of human properly. You do not see gay people as fully fulfilling this definition. This is the core of all homophobic arguments, and it is also the core of the arguments for racism, sexism, transphobia, ageism, audism, et al. Refusal to acknowledge the status of another human being as being principally equal to yourself. This translates very cleanly into animosity... Which in turn causes hate.
Thus, I say, regardless of whether or not you have the strength to come out of the closet and admit that you hate gay people, you do hate gay people. I cannot change your belief here, nor do I have any intent. I merely believe that you should accept your reality, and the fact that you are not the ideal Christian you would make yourself out to be. Examining the darker parts of yourself will give you a better understanding of yourself and a broader perspective of the world around you, and through it, God.