There is absolutely no hostility from any significant portion of the population towards what you would define as a normal marriage. At present, there is a great deal of hostility towards those who attempt to define marriage as only between a man and a woman (And the reverse is true as well of course), but that is not quite the same thing.
You're complaining about letting kids have toys of their own choice? Really?
The definition of marriage doesn't belong to Christians, it was around long before them, exists without them, and certainly has not always been only between a man and a woman. It is a social and legal construct that has been defined and redefined very very often throughout human history. Whether or not a person's marriage is of a type that your particular faith approves of is entirely irrelevant to its place in the law. Now, a different issue would be if religious institutions were being required to perform services for marriages they don't approve of, but that's not happening.
Transgender bathrooms is the one issue that I can understand you objecting to. But to be frank, its just a formalization of something that's already been happening. TG individuals have been using the bathroom they fit in best in for decades already, with none of the issues people are declaring would happen.
Challenge attempt #1: Homosexual behavior is not biologically necessary.
Answer: Technically true, but the same can ultimately be said of clothing, government, modern medicine, cities, nations, religion itself, and nearly every single aspect of everyone's lives that are not strictly necessary for survival much beyond childbearing age. Are you going to ban those as well? I asked for an argument against homosexuality, not a declaration that the species doesn't need it to continue.
Rather off topic, but...
P.S. I told you to use ethics and morals, not the opposite. My one limiting requirement was that the argument not be based on religion. This last bit is important, because even the Christian faith is not unified in its condemnation of homosexuality, the Christian faith's basis for that condemnation is on extremely shaky ground, and ultimately, this nation is based on the principle of freedom of religion.