"Christian" opposition to gay marriage is on the same level of dumbness as the Xenu story of Scientology.
No it's not. Xenu is all kinds of stupid. Opposing gay marriage is dumb in the same way forced public schooling is. You can make halfassed arguments for both, but at the end of the day the people arguing for either one just come across looking stupid and irrational to everybody that hasn't had that particular flavor of koolaid.
The only arguments against gay marriage boil down to bigotry. As least the Xenu story isn't inherently bigoted.