It's really not the same everywhere. I work for a big financial corp. Things aren't perfect, but we do everything in our power to support women on maternity leave, and that kind of behavior would get the manager fired.
That's great to hear. But one reason bad things happen is that people, especially management, believe in their company's good intentions and policies and don't realize that the reality is much different. The only way to know is to observe what actually occurs. (Of course, I'm speaking generally; I have no idea what happens at your company or what you know.)
A similar situation occurs with health insurance. People trust their insurance and assume it works until they get sick and learn the reality of it.