You are playing a word game by using generalities so you can avoid analyzing the actual application in specific instances. My analysis will provide consistent results, although I suppose you could argue I was being lazy by using "man" and "woman" and should have clearly identified specific individuals.
Assume John Doe, a black man, and Jane Doe, a black woman, are siblings; Mary Smith, a white woman, is unrelated to them.
John Doe and Jane Doe CANNOT get married.
John Doe and Mary Smith CAN get married.
Jane Doe and Mary Smith CANNOT get married.
The specifics help us identify whether and how a law discriminates. Jane DOE and Mary Smith are treated differently, based on familial status, so we analyze whether <arguments against incest> constitute a legitimate purpose. John Doe and Jane Doe are treated differently, based on gender, so we analyze whether <arguments against SSM> constitute a legitimate purpose.
Here, let me demonstrate why it is important to use specifics:
Jane Doe can ride Bus #247
Mary Smith can ride Bus #247
Jane Doe can ride on at least one end of Bus #247
Mary Smith can ride on at least one end of Bus #247
Jane Doe CANNOT ride on the front of Bus #247
Mary Smith CAN ride on the front of Bus #247
We are finally showing discrimination, but even better:
Jane Doe CANNOT sit on the first seat of Bus #247
Mary Smith CAN sit on the first seat of Bus #247
The above example shows how analyzing specific can show hidden discrimination. Analyzing specifics can also work the other way, to show a lack of discrimination.
Jane Doe, a private sector employee, CAN be fired without due process
Mary Smith, a public sector employee, CANNOT be fired without due process. BUT, with specifics we see:
If Jane Doe is hired as a second grade teacher in classroom #2 at Rising Star Public Elementary School, she CANNOT be fired without due process.
If Mary Smith is hired as a second grade teacher in classroom #2 at Rising Star Public Elementary School, she CANNOT be fired without due process.
If you analyze specific circumstances and test whether specific individuals are treated differently in those circumstances, you have a consistent means for identifying discrimination.
