I think its worth considering as an action of Stack Exchange Inc, as opposed to "Stack Overflow" as a website. Corporations might not have a conscience, but the people within it do. And sometimes they feel the need to use the tools and platform they have on hand to do the best they can.
Unlike Google - an protest at SE wouldn't exactly hit the news. Overdone, it would kill things off, but once in a while its good for us programmers and non programmers alike to peek out from our keyboards and go "Hey, there's something going on".
Meta's about as good a place for this as any for this. There's some condoned meta content that's not quite just about how the site is run, but also about the community.
Amongst the things that meta is meant for is
Stack Overflow the company to communicate with the community (soliciting feedback on new ideas or features, or discussing policies that affect the whole network)
I did talk about the conscience of the people of a company right? Well, this is how its communicated. This is how Stack Exchange Inc, the company, and the people who make it up go "We feel this is important" to the folks who make up Stack Exchange the community.
So, twice in 6 years? Talking about things that matter? I donno. I can live with that.
(Just for the record - and for full disclosure. I'm a mod at superuser.com. I fully agree with both of the posts that could be referenced here - both the original SOPA post, and the recent (2017) trump/immegration ban related one. Any views here are my own. They do not reflect the feelings of my fellow mods.)