Conflation of Proposition 8 with racism/slavery is a bit rich considering that black Americans disproportionally voted for Proposition 8.

But I suppose it's useful to drag out the racism comparison to demonize Brendan Eich, although you don't want to stretch the metaphor too far since it might make people wonder how "inclusive" the American technology industry is of black people, "old" people (i.e., older than 35) etc.