Earlier quoted context omitted.
This has ethical reprecussions on the news ecosystem because whichever keywords/mentions that Facebook dictates as political will be targeted by news organizations to avoid. These organizations will strip normal news of any political connotations which is frightening because the news, although mostly a pile of noise today, is supposed to have signals to keep democracies in line by design.
I would argue that stripping news of political connotations would be a plus. I wish all news was reported this way.
If politicians are doing things that stress you out or make you angry, would you really be better off staying uninformed? I'm not saying that Facebook is a good way to accomplish that, just that it's worth considering before you ask for technology to seal yourself off from political news altogether.