The attitude was that "no hetero would do that sort of thing." A similar attitude for race relations would be to use the "one drop rule" [0] against white-looking [1] supporters of civil rights for blacks (back in the 1950s & 1960s), that since no white would do that, I must have some black blood in my ancestry and therefore I'd be legally black.

> In the United States, the “one-drop rule” — also known as hypodescent — dates to a 1662 Virginia law on the treatment of mixed-race individuals. The legal notion of hypodescent has been upheld as recently as 1985, when a Louisiana court ruled that a woman with a black great-great-great-great-grandmother could not identify herself as “white” on her passport. [2]

> Not only does the one-drop rule apply to no other group than American blacks, but apparently the rule is unique in that it is found only in the United States and not in any other nation in the world. In fact, definitions of who is black vary quite sharply from country to country, and for this reason people in other countries often express consternation about our definition.

> The phenomenon known as "passing as white" is difficult to explain in other countries or to foreign students. [3]

This happened back in the 1990s. In 2007, Florida repealed the ban on homosexuals adopting, but I had left the state years before.

0 - https://en.wikipedia.org/wiki/One-drop_rule

1 - https://en.wikipedia.org/wiki/Passing_(racial_identity)

2 - https://news.harvard.edu/gazette/story/2010/12/one-drop-rule...

3 - https://www.pbs.org/wgbh/pages/frontline/shows/jefferson/mix...