Does Anyone Know The Rules Governing The NFL?

A friend of mine suggested that another bad call occurred in the Super Bowl when Seattle's Darrell Jackson caught a ball with his left foot inbounds and with his right foot first touching the end zone pylon and then landing out of bounds.

I didn't think the call was controversial, BUT my friend e-mailed me this ESPN article from John Clayton discussing some recent rule changes. The pertinent portion provides:

A player will be ruled in bounds if he touches the pylon at the goal line before going out of bounds. For example, a pass would be considered complete if one foot touches the pylon and the other foot is in bounds.

I'm not surprised that the average fan would be unaware of this rule, but the fact that the announcers, referees and even the replay officials (the play occurred within the last 2 minutes of a half) were also unaware is simply astounding.

I decided to double check the rule. First, I went to NFL.com and found it only provides a summary of the Rules. I found that rather bizarre.

Second, I googled NFL and "official rule book" and found that Amazon sells a copy. Yet, as the one commenter who purchased the book states, the copy being sold is not complete but abridged and edited.

As it turns out, the NFL does not make its official rule book available to the public.

Why don't they?