They no longer participate in society. No marriages. No offspring.
You think people are going to stop fucking because they are mad at politicians...? Or that people would cause their own economic downturn and willingly give up their jobs, and in turn food & shelter? Uhhh... No thanks.
Ever heard a phrase to the effect 'This is not a world I would want to bring a child into'?
Between abortions and contraceptives there is no need to stop having intercourse, just stop having babies. Without immigration, the population of 'first world' countries is already shrinking.
Also, the worse the economic climate, the more people will save their money against future problems. Not everyone, but those with discretionary income will be more inclined to save it up or put it somewhere safe as opposed to making more purchases or making riskier investments.
Have you heard the phrase 'jobless recovery' much in the last few years?
I doubt it is any sort of intentional protest, but if people do not have confidence in their leaders, they will tend to hold back.
(if you are stuck with the choice between Trump and Hillary, and the one you want least wins, will you celebrate by going out and buying a car?)