I'm sure it mostly amounts to naval gazing, but it makes lots of sense that liberals would be tuning out of politics. 2012 brought major victory at the polls, but gerrymandering kept the US House in control of Republicans despite a couple million more votes for Democrats, the filibuster prevents the US Senate from functioning properly, and our most liberal prezidnt evah spends more effort on going after whistle blowers, drone bombing social outing in Afghanistan, and trying to destroy the welfare of future elderly by cutting the safety net in the name of deficit reduction brought about by wars and tax cuts for the rich than he does on issues and efforts that would actually improve the lives of Americans.
So, yea, from a liberal perspective it's pretty fucking obvious that politics aren't worth the effort. The US population overwhelmingly prefers liberal policies, and sizable majorities are at least sensible enough to recognize that popular policies are less likely with Republicans in charge, but the engaged liberal is starting to recognize, that conservative policy is what we get no matter who is in charge. That is disheartening, depressing, and distressing.
In the wake of a sizable electoral victory we have seen liberal policies lose out repeatedly: the tax cuts were all going to expire, and instead we got most of them continued, other than the top tier only...oh, and the payroll tax cut that was a much bigger increase for most people; the sequester kicked in, and as it gets worse and effects more people we hear less about it; the gun control legislation that everyone was so sure was going to pass this time...didn't pass; the president's very disturbing war on whistle blowers has been ratcheted up, as has the horribly immoral drone bombing of any male of at least 16 years over there.
People want medicare for all, and more generous social security, and less remote controlled murder and punishment for crooked banks and banksters, and help with student loans and home debt, and for the love of god, sensible energy policy. We get none of that. Ever. Rich people still pay next to nothing in taxes, and the gap widens and families go hungry. So, yea, for a liberal, tuning out politics is a healthier alternative.