what do the anti's mean by unnatural?

I agree with all the excellent points you made, but since your question is "what do they mean when they say it's unnatural?", I will attempt to answer this from what I have heard from both personal acquaintances who are homophobic, as well as what is out there in mass media.

My theory is that when they say "unnatural", it means personally, for them, they cannot see themselves engaging in sex with the same sex. Some have been very blatantly vociferous in their expression of disgust, one person I knew actually spat on the road, because he felt he was about to throw up, at the thought of two men kissing each other. (His exact words: "Why the HELL would any man want to have thick lips on his own, a moustache or stubble grazing his skin, and hearing a grunt, when he can have soft supple lips, smooth clear skin to caress, and hear a female cry out in ecstasy?!?)

In short, they CANNOT see themselves doing it, and of course, for that person in question, it would be unnatural, because the are naturally drawn to (in the example) soft supple lips from a woman.

In much the same way that I, as a gay man, would also throw up at the thought of a physically looming vagina, I need to scour my brain with ultra strength cleanser to wash away the thoughts - yuck -because I am naturally drawn to men, by NATURE.

Unfortunately,what the homophobes think is unnatural to THEM, is the only thing that IS unnnatural. (Or, to put it roughly, "because we said so!") And that is truly an intolerant view. They cannot see the perspective of someone who does not share their "natural-ness", that as a gay person, I am totally in opposition to what they would consider as "natural".

And of course, they trot out the infamous Bible, to back up their claim, the famous Leviticus chapter about not "lying with a man". Of course, they choose to ignore the verses in that very same chapter about shellfish, wearing pearls, cutting off your hair, etc, all all being "abominations".

What could be more naturally appetizing than a plateful of crabs!

As far as logical points can be said to be made by such statements there are two:

1. You cannot get pregnant via anal sex.

Of course this ignores all the other sex acts which cannot possibly result in pregnancy. This is often justified by saying that at least these are between people who can also achieve pregnancy unlike homosexual acts. And this of course ignore the huge number of sex acts between heterosexual couples for whom at least one is reproductively impotent. For instance, should all women past menopause be divorced so that their husbands can have sex with someone who is reproductively viable.

It also is an attempt to erroneously suggest that the only purpose for sex is reproduction. This is in not true either in the human population or in many animal populations. Animals use sex for non-reproductive reasons including pleasure and bonding.

Even the vast majority of fundamentalist religious groups support finding pleasure in married relations. It is only when homosexuality enters the discussion that reproduction becomes the sole purpose of sex (or marriage).

2. The anus is not designed to receive penetration.

Even in Christian churches, the anti-gay ones, there can be very graphic, though incredibly exaggerated, descriptions of things like anal "tears" that occur during sex. What they don't tell, and probably don't realize, is that such things happen during vaginal sex as well.

Sex, all sex, is dirty. It all involves use of excretory organs. Physiologically, the vagina is actually a very "dirty" place. They are filled with bacteria and other pathogens even under the healthiest of conditions. Many people can remember from their youth having to get over ideas like, "you want to put what where!?"

The genitals have an enormous number of nerves designed to stimulated for pleasure. We are obviously built to find genital sex stimulating and rewarding. The anus has nearly the same number of nerves for pleasure. No other place on the human body comes close to these two. In the first case we find it obvious that pleasure is intended; in the second we're supposed to pretend that we don't know what the intention was.

Anal sex DOES occur in the animal kingdom, as well as other homosexual relations. There are many natural functions anal sex can provide in the human population, hetero or homosexual, including both pleasure and emotional bonding while providing reproductive control for one the few animals which are always "in heat."

Look, this is really just about prejudice and cultural taboos. In racist cultures, the oppressed race is often described as being in some way unnatural. These attacks are just about demeaning a group of people, and threatening others about how they will be viewed if they choose to be gay, or gay friendly.

These people who say that homosexuality isn't natural do not have enough research or information. They may be referring to the fact that women cannot get pregnant by another woman, and vice versa. Men and women "naturally" fit together. But then again, there are gay animals and expirimentation has existed for thousands upon thousands of years. I, personally only understand the pregnant part, but nowadays there are other methods to getting pregnant. Is that not natural? The human mind is natural, and anything we do comes from the mind. So in my opinion, homosexuality is completely natural.

Nothing is 'unnatural' 'Unnatural' doesn't exist. If we do it then it is natural. Homosexuality is as natural as heterosexuality. Remember the human brain is a product of nature the same as every living thing on the planet. If nature has decreed that some humans will be Gay then that is natural. Those who are 'anti-gay' have a political agenda. Unfortunately hate is natural too.

What an interesting question!

Well, in my experience of life, those who openly condemn an activity are the very ones who would like to try it.

So how exactly does one define "normality?". God only knows!