When I was 17 and in a young democrats club at my high school we attended a very contentious protest around whether or not the county would become a sanctuary and there were a ton of activists coming out, both for and against.

Generally activism happens on the county level rather than city because columbia isnt actually incorporated. I'd say if you're looking for progressive folks to organize with and stuff look for the unitarian churches.

Columbia itself is mostly split between the "moderates" who don't like public housing and don't want their school districts to be connected to them, and the progressives who are fine with it. The older areas like oakland mills, long reach, owen brown etc will generally have more progressives while the newer places like river hill will have more "moderates". Generally the republicans and whatnot are in western hoco and you wont see many unless you go out to clarksville and beyond