It saves people a nasty surprise when the policies they relied upon fall out from under them, or to try and head off future issues by calling up their representatives. For example, I was able to call up my representative regarding changes in immigration policy. Because other people aren't paying attention and don't call their representatives, I actually have an outsized voice and influence on the matter!
RE becoming politically active: it's good to be informed, I totally agree. But that's not something you get from the news. I can't imagine you watching CNN and saying "whaaaaaat? I'm going to call my representative right now". You'll usually have that filtered by whatever organization/initiative you delegate that to. They will relay the important stuff to you and ask you to become active. That's very different from watching the news imho.
Use a filter by reading a monthly or quarterly publication. You will get the information (that's still considered print-worthy after the next news cycle), but not the hectic, emotional manipulation and outrage.