Subject of a participle clause

Hello.

"A detailed examination of the world's greatest inventions highlights the perpetuation of the myth about the instant Big Idea, masking the reality of the incremental process at work." (Creativity in Public Relations, Andy Green)

Here, what is the subject of "masking?"
"The myth" seems to be, but I've known that an object cannot be a subjecy of a participle clause, just as "She loves books making her cry" doesn't make sense. (I questioned about this before and learned it here, on this web, but I wonder "I like people walking on the street" doesn't make sense neither.)

So there are two questions:
1. what is the subject of "masking?"
2. Is "I like people walking on the street" correct?

Thank you.