I can see where you're coming from, however...Did you message the mods of /c/politics & ask if they might consider changing their display name to more clearly indicate their US focus? It's not ideal, but the display name is what's shown when searching for communities or seeing posts from them in local/all feeds, so it at least helps in that regard.

At the same time, as other comments point out, there are a number of other politics communities with a broader focus across other instances, so unlike Reddit, we can have a /c/politics in any number of other instances with different rules and without a US focus. In a weird way, it's almost better that the /c/politics here is US focused, as it encourages folks to post & discuss general politics (including the US) in other smaller instances.

Although, ultimately, this would come down to whether the admins would prefer such simply named communities to have a wider focus as their name suggests instead of a narrow focus as is happening here, but I haven't gotten the sense that the admins necessarily want to get that directly involved in community naming & creation tbh.