In 2008 when Proposition 8 was on the ballot, that Eich privately supported, even President Obama (candidate at the time) was publicly against gay marriage.
There needs to be some historical cultural context, supporting Prop 8 in 2008 is different than supporting Prop 8 in 2023. Now if Eich said he would support it in 2023, that's a different matter.
But I would still use Brave browser and search since it's a good product.