Because you want information you don't have, and that aren't placed in the public domain, that's why..
It is usually code for you needing to have an NDA or license in place for them to disclose the technical info / trade secrets.
Standard operating procedure, places like SiLabs, Broadcom, Marvell etc often only allow viewing via a secure portal with no ability to print or hardcopy materials, and limited to specific named individuals.
Tips, Buy me a coffee, or three.. PayPal Venmo (See Profile) Up vote any posts that you find helpful, it shows what's working..