Why do software developers accept this? It's the only profession i've heard of things like this happening. I've never had an employer even think that anything I

Why do software developers accept this? It's the only profession i've heard of things like this happening. I've never had an employer even think that anything I make or do in my own time is their business, even when i've used materials or equipment from work. The idea that an employer has any rights to anything I do they aren't paying me for is mind boggling.