Restriction to share is a big thing indeed, especially if you work for vendor. Lot of software running in the background checking on you.
But i believe in general telecom world is just too different from programmer’s. It’s much more “corporate”. Companies we work for are competing with each other - vendors, operators. By answering somebody’s question you may just be helping your competitor. Your superiors or clients might see your answer on the forum (or even easier - whatsapp group). Willingness to help may hit you back really bad.
And other major difference, - it’s just so easier to become a programmer, there are so much more programmers in the world (~25 millions and growing). You may be a dentist in Nepal, but having talent, computer and some internet access you are good to go. It’s really easy to start programming as a hobby, for fun. Read stuff, try to replicate, share your findings with others. If things go well, in a while this “fun” brings you money. Now telecom … at least talking about telecom operators … totally different story. You may spend a year reading O’Reilly’s books, but unless you live in a right city, studied at a right place or have a good relationship with somebody who is already onboard, most probably it won’t really take you anywhere (at least in Brazil). And you can’t just do something by yourself hoping it will be useful for somebody in the future … without access to telecom world, you simply won’t know what kind of issues people have, which problems are there to solve.
But perhaps it will change soon. Seems like telecom professionals are slowly migrating to programmers. Every time we see more automatization, more tools being developed … replacing telecom professionals. So, probably in a while the comunity will get better :).