Huh?
Your argument was that the people should vote on civil rights.
Stick with one argument.
Since you seem to like to change your argument and go in circles, I'll just write them all out and the rebuttals for each.
1. The purpose of the anus is not for anal sex.
Has nothing to do with marriage because either heterosexuals or homosexuals could engage in anal sex. Lesbians don't engage in anal sex. And neither the government nor you has any business with what people do in their bedrooms.
2. Same sex marriage would allow for alternative forms of marriage.
There is a strong evidence base supporting same sex marriage that does not extend to other forms of marriage such as polygamy or incest. This includes evidence which shows that both partners benefit from marriage and same sex couples are just as capable of raising children as different sex couples. Given that the civil purpose of marriage is to provide for stable relationships and homes to raise children, these are vital factors which the evidence supports for same sex marriage, but not for polygamous or incestuous relationships.
Also, the number of children being raised in polygamous and incestuous homes is very small, but 8 to 10 million children are being raised by gay parents and same sex couples, which indicates a large population of young people who could benefit from same sex marriage.
3. The people should vote on same sex marriage.
This is a Constitutional Republic, not a Democracy. The founders of this country envisioned protecting the rights of minorities from the will of the majority. In doing so, they created a system of checks in balances, whereby the legislature and the Supreme Court could protect the civil rights of minorities. Hence, it makes no more sense to have people vote on same sex marriage than it would have to have had them vote on interracial marriage. For that matter, just because a majority is against an idea, does not mean the idea is wrong. Most people were against interracial marriage, but that doesn't mean interracial marriage was wrong then or is wrong now.