It's likely an internal microphone and speaker; the sound card may not support input through that interface. What you're saying can be true for many other modern computers, though.
I (personally) think that intelligence/privacy-wise the mic on many devices is a lot more troubling than a camera. Camera is very directional and (again, personally for me) would at most result in embarrassment? While a microphone can record all conversations in a room/appartment, transmit everything with fairly negligible bandwidth, and taping over it won't do much good. You actually need to open the device and disconnect/cut a wire.