Not to mention pedophile and bestial lovers. If marriage changed definitions from "Two people of the opposite sex of consenting age..." to "Two people of consenting age...", then "Two", "consenting age", and "people" are all up for grabs.
Not to get in the way of your hysteria, but I’m not aware of a any uptick in the number of man/dog or man/child marriages in the wake of the Loving v. Virginia decision, in which an activist Supreme Court said state bans on blacks and whites marrying one another violated the constitution.
If suddenly white men being able to marry women of any color didn’t also mean they were allowed to marry, let’s say, ducks, I don’t know why saying they’re allowed to marry other men would have the same effect.
You're right, nothing is rational, let alone sacred. You're liable to get verbally shot at by the FLDS folks here about.