The “Not My President” Movement

There’s a voter meltdown going on in this country as seen with the “Not My President” movement. Your candidate didn’t get elected? You now can become a 2 year old, stomp your feet, hold your breath, cry incessantly, and throw a hissy fit. You can now cry that the winning candidate isn’t the “legitimate” winner. This is now the norm.
Did we forget? 1. George W Bush wasn’t the “legitimate” President because he was “selected and not elected”. 2. Barack Obama wasn’t the “legitimate” President because he “wasn’t born in America”. 3. Donald Trump isn’t the “legitimate” President because a)he stole the election, b) Russia hacked the DNC server and impacted the election , and c) he didn’t win the popular vote.
Well, my candidate didn’t win and was prevented from fully participating in the election cycle but I’m not acting like a spoiled 2 year old. If I did then no matter which one was elected I could embrace the idea of “Not My President” if Clinton would have won instead of Trump. I’m not happy but someone has to be the adult.
But can anyone remember the last President elected whose election wasn’t doubted as “legitimate”? The last one I remember was Bill Clinton’s. After that, when the Royal Family Clinton highjacked the Democratic Party, the legitimacy of his successors began to be questioned (see above). It became tit-for-tat. Coinsidence?