It isn't that P90X doesn't work or that it is easy to make fun of, it is that people are SHOCKED and SURPRISED it works.
Take fat, overweight, out-of-shape people and get them into a workout routine that is somewhat balanced. Give them tips on how to fuel the body and voila.
This isn't an AMAZING success principle, it is what every workout routine is and like S34n05 said, it is free everywhere online especially in other, more helpful communities like Reddit/r/fit or even 4chan/fit
Fuck BB can be useful if not for its crazies.