I'm waiting for the FR moral relativists to proclaim marriage among gays does no harm. Or to ask me "What harm does it do?"
Such ignorance does not deserve an answer.
What harm does it do?
The point of the article (made unwittingly by the authoress) is one that I and others have already made here many times-the harm is real, all right, but it's already done.
Pretended marriages by homosexuals became possible only AFTER thirty plus years of pretend marriage between men and women. The legal institution of marriage was eliminated in America between 1969 and 1975 (see the excellent Why No One is Married for the full argument).
Since legal marriage became a temporary at-will arrangement to collect loot from others, it became untenable to refuse the benefits to those who did not wish to "marry" opposite-sex partners.