
Set aside the obvious possibility that some prior elections were, in fact, more important than some future elections will be. Also set aside the absurdity involved in making claims like this in the absence of anything we might use as an agreed-upon metric of an election's importance. What are we left with? Aside from hype and hyperbole, we are not left with much.
Recognize that the claims about every election being the most important ever are appeals to emotion. They are designed to manipulate you into doing something the person making the claims wants you to do (e.g., vote for his or her preferred candidate, join his or her activist cause, participate in the mindless tribalism which afflicts our nation by demonizing his or her opponents). By inflaming your passions, you become less susceptible to reason and far easier to influence.
As a freethinker, you might see through these attempts to influence you. You might recognize them for what they are and opt-out, refusing to play the game. You can vote for whoever you like, or you can not vote at all. You can contribute to whichever activist causes you wish or contribute to none at all. And while I'm hesitant to say that you should claim to be a freethinker while abandoning reason in exchange for tribalism and demonization of "the other" (because you'd then deserve the charge of hypocrisy), you certainly can do that too.
The 2016 presidential election might not be the most important election of our lifetimes. It might not even be the most important election that has taken place during the past 20 years. You get to decide how important it is to you. If you'd like to devote every waking minute to it, you are free to do so. And if you'd prefer to tune out all the noise around it, you may do that instead. This is just one aspect of the freedom that comes with freethought and the rejection of tribalism.