While I have no particular opposition to allowing civil unions personally if a state wishes to, I am simply not an advocate of it.
Homosexuality isn't natural at all. I am aware of some studies claiming it to be normal behavior in the animal kingdom, but I consider these to be biased and unscientific studies that generally confuse what they are seeing (domination acts as homosexuality), and as a simple example most everyone is familiar with, male dogs humping each other is entirely domination behavior and not sexual. I suppose you would consider incest natural too, since these same studies highlight the acts of incest within these animal communities such 'studies' were observed on, commenting on how the 'cute little ones' eagerly participated too.
I have heard this argument from fundamentalists throughout my entire life (especially with the dog and horse examples). In those cases, it can be a form of dominance (though one can also argue some sexual behavior does involve dominance no matter the genders). But you do not account for the other 1000+ studies involving things such as placing electrodes on the uterus's of two female monkeys and monitoring the contractions they give each other. They are obvious forms of pleasure that are documented. Birds can form homosexual bonds that are sometimes life-long. Overall heterosexual or homosexual behavior in all animals (us too) serves a huge variety of social and psychological aspects, and simply saying it's all about dominance is a bit ignorant of everything else. If it's seen and documented in nature numerous times, it's natural behavior.
Comparing it to incest is a strawman argument and I'm kind of surprised you wouldn't catch it in your example- incest can produce damaging problems genetically and therefore is undesirable in procreation. It can hurt the baby. Incest is mostly seen between an adult and a child, so again, it could be argued that an innocent is harmed (rape). Homosexuality is completely consensual and does not allow for procreation or forced relations, therefore cannot be directly compared to incest.
Personally I find the entire matter rather disgusting and depraved, but if it is what you like then I suppose that is your business, just don't try to push it on me as if it is something natural or desirable
I hate to dive into personal aspects, but just between us dudes- if you ever masturbated to hot lesbians before, your argument is completely hypocritical.
How exactly, would allowing same sex marriage between two consenting adults be pushing it on you?
In the same sense that allowing blacks to vote would be pushing it on a white person.