In contradiction to your reasoning:
A) Not everything on the internet you see is true. And not only that, it doesn't help you develop the necessary social skills needed in life. Plus, it makes you gain weight and worsens your posture, though if those aren't issues so be it. As for the history channel, it's not like you'll learn everything that you need to learn there, unless you wanna be a historian or something along the lines of that. But then you should still pick up a book on certain events and read it. Learning through reading > Learning through watching TV/going on the internet anyday.
B) Laziness is a poor excuse. Tests are reflections on what you learned, and they're there to make sure what you've learned is stuck in your head. This doesn't mean you have to study for hours on end; I hardly study and still do well on tests. The environment you're in might also affect test-taking. I get to change classrooms at my school so I'm in a quieter and much less anxious environment while taking tests.
C) First off, be aware you're being a hypocrite (unless you do believe that about yourself), and that you may offend some people on here. Next, while there is the occasional idiot or two in school, there are still many teenagers who are much more mature than they look, and actually care about school and grades.
Yadda yadda yadda You don't have to listen to me if you don't want to.