[kevkrom]

I'm not confused here, the endzone is inside the lines ergo you must cross the line completely to enter into it.

Yes, you are confused. The entire line is part of the end zone -- by rule. It doesn't matter what you think, or what I think, it matters what the rule book says.

You're thinking of soccer or hockey, where the entire ball/puck must cross the goal line. That's not true in (American) football.

[usmcobra]

The entire line is part of the end zone -- by rule.

Can you show me in the rule book where it says that?

The line along the back of the endzone is a boundry, the lines on the sides are boundries, and yet the goal line is not a boundry but part of the endzone.

That honestly doesn't make sense. The Goal line should be one more boundry that defines where the endzone ends and begins.