If you think that the integrity of the fundamental societal unit is not a matter of some gravity, then I'm not going to be able to explain it to you. I don't mean to be condescending, I once held much the same opinion. Observation and experience has led me to a different conclusion.
Lawrence has put the SCOTUS on a collision course with the institution of marriage. The homosexual lobby can taste it. To prevent that, an Amendment like this is going to be ratified, so your best bet is to try and make sure we get the best one.
From what I know of you, I'd expect you'd agree that the societal unit is breaking down due to government meddling. There are few consequences to any actions, hence personal responsibility is not a prized trait among many.
How is an amendment going to change any of that? Legislation of morality never works, and I suspect you agree with that. Is this logic talking or anger?