Is there any secular reason why being gay is bad?

[kılıç_mehmet]

Thieves, murderers, traitors, and provocators affect other people in a negative way. Homosexuals do not. They only affect themselves and their partner (who has consented, assuming this is not rape).

Well, in the case they do not interfere into the current normal society by demanding special rights for themselves, they are not breaking social harmony. Everyone can agree with that.
However, if they try to act as a thief would, who sees the other man's property as his own...As the current liberal ideology states how we should be treating "sexual minorities", like allowing them to participate into society using their sexual identities, is like the thief's work. They see the society as their own, where they may act as they wish, with no one having a say on their deeds.
No, friend. Such actions cannot be tolerated once they go public.

How do homosexuals not live in harmony with heterosexuals?

They do try to bring heterosexuality on the level of homosexuality, or try to elevate their condition to the level of heterosexuality, don't they?
They try to destroy the existing harmony.

They are not asking that heterosexuals should be treated any worse,

Not that they can, they can't. Who are they to suggest such a thing in the first place?

they are simply asking that homosexuals should be treated equally,

I've said it a couple of times that equality is only amongst equals. If they want to be treated with their national identities, ethnic identities, religious identities, or whatsoever, they would receive the equal rights within these contexts.
However, they prefer to be treated by their sexual affiliations. According to this, they will receive their treatment. Heterosexuality and homosexuality are not equals of eachother. A homosexual might be treated as an equal within the "homosexual scene", but within society, that is built on the norm of heterosexuality, they cannot expect equal treatment.
And I guess one could agree on the fact that society has always accepted heterosexuality as the norm.
Those who wish to break this norm, act against the natural harmony that exists between anyone.
Will there be a time, when people will associate themselves with their existing sexuality, rather than anything else? Then we will be doomed.

which is fair.

Forcing the public to accept their condition as an equal with the normal standards which lead our lives, and labeling others who oppose this as "bigots" is clearly fair, I assume.

---

You really are a moron if you think the "coming out process" is some kind of adoption of "gay" as your prime identity. Plenty of gay men come out and then don't ever mention it unless someone asks, or it is sensible to mention it. One of my gay friends came out last year and I've never even heard him utter the word. Coming out is a personal thing; it is letting people know who you are, that is all. There are people who adopt a more flamboyant lifestyle than others, but that is true of everyone.

Is it not? I think it's the same for you atheists, if not, you'd not be here.
It's the same for us Turkists. We have adopted Turkism as our primary political identity, with which we present ourselves before fellow Turks and other people of non-turk affiliation. Similarly, homosexuals do this.
Besides, you do not need to mention anything by word. Do I specifically tell people that I'm a Turkist? I don't have to. They understand this by my views on certain subjects, or the way I act towards people, the way I act in public, the articles I publish, or the "likes" I have on my facebook.
Similarly, homosexuals who come out, come out with their homosexual identity.
These recent times have seen the collectivisation of this homosexual identity, where a subculture was created. Perhaps not all around the world, but the fact that it exists in the USA, a country which is the prime exporter of popular culture around the world is a threat.