You realize that LGBT is a lifestyle and that what you just said makes you look like Jim Jones, right?
Human Sexuality isn't a lifestyle, it's a sliding scale of sexual attraction, but it can result in certain lifestyles, and I don't give a damn what it makes me look like, it happens to be true.
OK, let me rephrase it: Sexual orientation is transitory (Anne Heche) is environmental and therefore behavioral. Better?
Behaviors aren't protected in the Constitution except religion. When will LGBT be applying for tax-exempt status? Also, compulsive theft and bulimia are orientations of behavior. Where are their guarantees? When LGBT "marriages" strip children involved of one blood parent 100% of the time or one complimentary gender-as-role-model 100% of the time, they don't have marriage rights. The state (and the fed by extension of the states, who derives its power only from the states...remember polysci?) only interest in marriage is to incentivized the best formative environment for children. All other concerns...as you say...the state "doesn't give a damn about".
It just so happens that man/woman is the best incentivized arrangement to ensure any children procreated have both blood parents in the home or at least both complimentary gender-as-role-models in the home..