Rats! (and other much uglier epithets)

I was just reminded that if I post the whole thing online here I potentially lose first publication rights and so lose a chunk of money. Since I am immensely egotistical and am certain this will be worth publishing, I don't want to do that so I'll stick to ideas and characters and plot development and reports on progress and I'll hide the real thing away somewhere NOT public so it can remain a secret officially.

Why are publishers so creakily hidebound about this stuff???