Well most Americans dont really care about these types of issues as long as their taxes stay low enough or go to the right places. Only conservative or liberal zealots really care enough to make big deals out of things like this anymore.
The ball to “issues” like this got rolling once they repealed the laws regarding interacial marriage and there is no end in sight.
If your question was how can frum people vote for people like this? Then the answer is simple, people who hold these kinds of views are very loose with other peoples money and tax dollars and will therefore increase spending on social programs. These social programs intended as a “saftey net” are instead looked at as a le’chatchila entitlement once you get married.
So the choice is, conservatives who want to cling to 50’s era values, or liberals that will make sure you can buy that brick of cholov yisrael cheese.
Complaining about the decay of society while taking the money from these same politicians is called “having your cake and eating it too”