Hawaii did so by ballot initiative because the legislature refused to do so. You cannot ratify an Amendment to the U.S. Constitution via ballot initiative...
You are correct, but legislatures (unlike judges) are directly accountable to the people. If the people overwhelmingly support a proposition, then legislators will go along, so as not to lose their jobs. Had the referendum option not been available to Hawaiian voters, they might very well have voted out the legislators who refused to listen to their demands.
I say we should take this amendment to the several states and let the democratic process run its course. Let each legislator go on the record as either supporting or opposing this amendment; then let voters re-elect the legislators who agree with them and throw out those who do not. It's a much, much better way of making an important decision than letting rogue judges impose their will on the entire country.
No kidding?