The fact that they can come out and say this demonstrates that these employees, the people best able to assess this, don't believe that Eich will retaliate. That Mozilla is and remains a place where any employee can express their views on political issues, even if they know they're contrary to the CEO's. And that destroys any argument for Eich's role as CEO creating a conflict with Mozilla's ability to welcome LGBTQ…
I don't know what the price of Eich's convictions should be, but I think that a good way to find out is for people who have been strongly affected by his convictions to say clearly what they think about it.
I don't know whether Eich will (or should) remain CEO, but whether he does or not, having people speak up in this fashion seems unambiguously positive.