So, whenever I turn my Switch on, a screen comes up asking me to press A three times. If I don't press it the system shuts off. Is there some way to disable this? I tried googling it, but got nothing in return. 

Three times.... Damn it should be no more than 1 time. I'd push B because I don't follow directions well.

Turn screen lock off in the system settings.

Agreed, the three button presses are attrocious, not even EA or Activision have gone that far as to have such sleezy and unacceptable mechanics.

Someone should start a petition!

The Wii made you push A to continue on health hazard screen on boot up (which if left alone for a min or two would automatically go to main menu screen).  The Wii U and 3DS launch auto to main menu without any button input.   Seems like an annoyance that one should be able to disable or they need to cut it to pushing it no more than one time.

System Settings -> Screen Lock -> Turn Off.

That's an unacceptably complicated and hacky work-around.

You should take a look in the Settings. So many interesting mechanics you will find there.