Here's an anecdote. I have a friend who worked at a tech company in the bay area (not Mozilla). He met and fell in love with a Canadian. They got engaged. At one point after a visit to Canada, they're both headed back to California for a visit. On hearing that the couple is engaged, the border agent refused the Canadian entry to the US: risk to overstay tourist visa.

Now, a straight couple could get a K-1 visa for the fiancé and marry within 90 days, but that was not available to my friend and his fiancé. Instead he was forced to leave his tech job in the bay area, uproot his life and move to Canada to be with the person he loves. That's the effect of Prop 8. That's what Brendan Eich was campaigning for.

There's a difference between working for someone who's different from you, and working for someone who's literally spending money and campaigning to break apart your family. Whose actions stripped away rights you had, and forced you to flee your birthplace to be with the person you love. So no, it's not the same thing. I'm tolerant of people who are different than me. I am not tolerant of people whose actions harm my brothers.