"Organized religion"...
A creation of mankind to cause mankind to feel is if they are serving God. Follows right along with the "step on a crack, break your mothers back" bit. Do this, don't do that. Eat this, but not that. Say what we tell you to say...sell this many books...get this many people to say "X".
In "religion", salvation (ie: attaining Heaven") is based on keeping to a set of standards set down by people who thought them up.
This is entirely contrary to a basic teaching the Bible. (Eph. 2:8-9)
From the Merriam-Webster Online Dictionary:
Main Entry: 1fun·da·men·tal
Pronunciation: "f&n-d&-'men-t&l
Function: adjective
1 a : serving as an original or generating source : PRIMARY a discovery fundamental to modern computers. b : serving as a basis supporting existence or determining essential structure or function : BASIC
2 a : of or relating to essential structure, function, or facts : RADICAL ; also : of or dealing with general principles rather than practical application b : adhering to fundamentalism
3 : of, relating to, or produced by the lowest component of a complex vibration
4 : of central importance : PRINCIPAL
5 : belonging to one's innate or ingrained characteristics : DEEP-
See highlighted (bold/italics) above for the best applied definition of "fundamental" when it comes to Christians.
Basically, most all "fundamental Christians" are extreme legalists. Adhering to the letter of the Bible, rather than what is the typically accepted interpretation, often only as it (Scripture) applies to other people, and not themselves.
No offense intended to anyone. This is a topic that I have spent years learning and studying about., and oddly can now debate the issues relating to it from most any theological position. (Not that there is a desire to do so, mind you.)
Mike