>Just look at this from the other side: you employ lots of people to work on some product, you teach them "secrets of the trade", send them to conferences, let them participate in making decisions, giving them extraordinary insight in the area of work you are active on... and as soon as they leave your company, they use all that knowledge to try to create something with that on their own (I can understand it, once you konw stuff and enjoy it, you want to keep working on it even in your own time), just for fun... basically spreading some of that knowledge you gave them and making it packaged and accessible not only to future contributors of their project, but to all competitors and genuine copycats out there.

Two things, first: You write like the company did the teaching, sending to conferences, allowing to participate ... out of the goodness of their heart. Obviously they did this because they saw a value in this, in fact they even pay their employees money to do these things.

Moreover, what do you think happens when people leave companies, they never use the knowledge they acquired? Do the companies continue to own that knowledge? Moreover, it even happens all the time employee leave and even found direct competitors to their previous employees. Just look at the founding history of Intel for a famous example. Also by the same measures we could accuse the repl.it CEO of stealing ideas from codeacademy and facebook where he worked previously, I mean he build an interactive website.