Census Bureau Encouraging Lies
That is nuts. The census is supposed to be answered truthfully. Encouraging one identifiable group to lie and and telling them that is okay to lie certainly sends a bizarre message to the citizenry. It is particularly bizarre because only states regulate marriage and not the federal government. It also treats one identifiable group differently than other identifiable groups, which has traditionally been viewed as not the American way, as in no-way.
It also is strange that the census bureau hasn't instructed man-woman couples to mark "married," if they consider themselves so. Here and there I have run into plenty of man-woman couples who "consider themselves married," (or at least the woman does, the man being possibly less than interested in marrying the woman) but that doesn't mean the couple is married any more than the gay couples are who are not married to each other are, or the old-fashioned Mormons, or that couple down the block who have been shacking up for years.