Puck.js with LDR - how to deal with light that is always on?

Thank you!
Can you please explain the code? I am a bit confused with all the "pullups" =)
So we set a variable pulledUp to true and counter to zero.
Then every 10s we check.
I am confused with the else part - if we set pulledUp to false during "stuck LED" condition, then the first IF will get executed after 10 seconds, which will cause a reading update?
Should it not be other way around? I am confused =)

  if (D2.read()) { // LED is off - all ok
    onCount = 0;
    pulledUp = FALSE;
  } else {
    onCount++;
    if (onCount>6) { // >60 secs on
      pulledUp = TRUE;
    }
  }

Also, what is the difference between

 if (!pulledUp) pinMode(D2,"input_pullup");

in the beginning and

if (!pulledUp) pinMode(D2,"input");

in the end? Or the first one suppose to be true and the last one false?