Questions about the details of public policy are being migrated. For example, I asked this question about SSI. It's a real-world issue of public importance. However, it was migrated to Money.SE.
Why was this migrated?
Commentor chirlu helpfully pointed us toward the question that spurred this meta topic.
Topics should be migrated when they are off-topic on the stack they are posted in, but on-topic in another stack (see the StackExchange meta post here).
In this case, the question is explicitly on-topic. Our Help page says:
Central to the idea of this site are the nuts and bolts of policies introduced by governments, presumably for the welfare of their citizens. As such, asking about the tangible benefits and costs of legislation is on topic.
When I first came to Politics.SE I imagined that this meant that the "nuts and bolts of policies" were on-topic. You seem to understand it the same way. After a lot more time wrestling with it, I think it's somewhat more complex. And unnecessarily so.
What this help document explicitly says is that questions about the "tangible benefits and costs of legislation" are okay. Costs and benefits can be interpreted broadly (that is, in non-financial ways), but your question is more about Social Security processes then costs or benefits. So it isn't explicitly on topic.
However, to justify that statement the Help document does say that the "nuts and bolts of policies" are central to this site. To me, this implicitly says that questions about the details of public policies are on-topic also.
Under this interpretation, which I admit is not entirely black and white, the users who migrated the question were in error. The question was on-topic here on Politics, and so should not have been migrated even if it was also on-topic elsewhere.
I'm a big fan of the idea, "Explicit is better than implicit.". Our Help page should be an authoritative guide to what is allowed or not allowed on Politics.SE. Unfortunately, it is not.
A long time ago I noted that our Help does not currently allow for political theory questions to be posted on Politics.SE. However, the community clearly supports it because these questions are posted and answered regularly. I tried to get the Help page updated, but it never got any traction. My own meta-post is here.
I've thought a lot about this since then. Overall, I'm convinced that the Help page and other pages are currently not helpful, and perhaps even damaging to the community. However, there is a significant lack of leadership in this community which prevents this kind of improvement. In other stacks I'm active on, it's common to see moderators actively developing community standards through meta posts, asking the community for guidance on issues, and using communal pages, comments, and other tools to help teach users to conform to the community's standards.
We don't see any of that here. Unfortunately, our leadership is also un-elected and relatively permanent. Since they are unresponsive to the community, it's unlikely that you will be able to improve the Help page without their unlikely benevolence.
Best wishes to you.