I think that you missing some of the argument.
The point is that, if the definition of marriage is changed by one group, then the definition of marriage can further change. It is going to be at the whim of a judge or interest group.
If the law allows marriage between gays, it is discriminatory to not allow others to have their own definitions of marriage. What gives gays the right to change the definition to fit what they want but others are denied their definition? Gays are being discriminatory.
Let's change it to a woman and her German Shepherd. If the male animal initiates sex, she is not forcing herself on Wolfgang. She would make the argument that it is clearly not animal abuse. Wolfgang is happier, he eats better, his coat is shinier, etc. Do you think some sicko won't make the argument?
If there is no history of abuse, why can't a grown daughter marry daddy? They will make the argument.
DFU: Or, how about two men and a woman or two women and a man?
PSYCHO: Not my thing, but I am not about to force my will on others.
You are part of the problem. Retaining the definition of marriage that has worked for centuries is not forcing your will on others.
Fine by me, so long as no one is hurt.
What gives gays the right to change the definition to fit what they want but others are denied their definition? Gays are being discriminatory.
No, you are being discriminatory. Gays simply are fighting for themselves. Not fighting someone else's battle is not discriminatory.
Let's change it to a woman and her German Shepherd. If the male animal initiates sex, she is not forcing herself on Wolfgang. She would make the argument that it is clearly not animal abuse. Wolfgang is happier, he eats better, his coat is shinier, etc. Do you think some sicko won't make the argument?
If there is no history of abuse, why can't a grown daughter marry daddy? They will make the argument.
Again, you are pushing the slippery slope argument. So just becuase someone is going to try to change the system further, you want to stop it now. I will fight the woman who wants to have sex with her dog. I will fight the father who wants to marry his daughter. Just becuase those two things should be illegal doesn't mean that gay marriage should be as well. In a way, this is a straw man argument.
The other problem with this argument is that in a way, you are conceding that gay marriage isn't wrong, but that it is similar to things that are, and so you want to nip the problem in the bud. Liberals make a similar argument with gun control (i.e. if people are allowed to have weapons, then irresponsible people will have weapons, and to keep weapons out of the hands of the irresponsible people, lets take them away from everybody).
Retaining the definition of marriage that has worked for centuries is not forcing your will on others.
Logical fallacy: appeal to tradition. Slavery went on for centuries. Did that make it ok? And no, I don't mean to compare gay marriage to slavery. I am simply trying to point out that maintaining the status quo is not a good argument.
Quite frankly, marriage does provide some protections that civil unions do not provide. I do not have the entire list in front of me, but I see no reason to not provide homosexuals the same rights and protections as heterosexuals.
Of course, like you mentioned, the next step for gays is the adoption of children. On that battle, I will fight on your side. However, I do not believe in denying rights to someone simply becuase I know that they will be asking for more once they get them.