What you wear -or don't- sends a signal just like hijabs do. Just as you see one and consider the wearer looks like a "religious entity", someone else will see you in jeans and consider you a "consumerist drone", or see your cellphone and consider you a "decadent bourgeois".

That you don't consider that part of "looking like people" is not the hijabs' wearer problem.

"like wearing symbols of oppression?" - According to whom is this a symbol of oppression? This is exactly the problem, if you ever to encounter a girl with a hijab you would automatically treat her differently because of her clothing, you've already attributed a persons religious clothing as a form of oppression. The point is to be respectful of others beliefs, not judge based on your own.