Laws are just a consequence of an actual cultural change, and can only succeed (and not precede) the conversion of hearts and minds. Voting and democracy should not become a device to placate the dissatisfied masses into silence, make them lineup for ballot, to choose a lesser evil who, in most likelihood, will turn out to be a egotistical power-seeker. We shouldn't conflate voting with "will of the people."
So I partially agree with you - there must be a certain culture change happening, but it can and it should be supported by law in order to happen faster.
According to Pew, gay marriage was supported by more people than opposed it in 2010, a full five years before legalization.
Not even leaders for the liberal party, like Obama and Hillary Clinton supported it until a few years later.
https://www.pewforum.org/fact-sheet/changing-attitudes-on-ga...