Marriage policy is marriage policy. Redefining marriage to include new unions is a policy issue more closely related to setting a tax rate or something else that is policy (not rights) based. Majority rules, that's democracy and within the state's rights. When sexuality is a protected class in the constitution like race and religion then you may have an argument. It's unconstitutional to deny people the ability to marry based on their race, it is within a state's right and policy to not redefine marriage to include new unions like ssm.
As to the poll question, of course it's right for people to stop or try to prevent ssm from being legalized. They have every right to vote on their beliefs and stop something they believe is wrong just like anyone else.