You are misinterpreting the point of the indicator.
Your iPhone has a microphone and camera(s). These are devices that can be used to listen or see.
So it's a privacy concern right?
The orange dot simply tells you that your microphone is being used. The green dot tells you that your camera is being used.
About the orange and green indicators in your iPhone status bar - Apple Support
When on a phone call, clearly the microphone will be used.. it's not something you need to monitor while on a phone call. But if you look and see that it's on, it should not be a surprise or a concern. Same concept for a FaceTime or Zoom call, with the green dot.
What these indicators should do is alert you to microphone and/or camera being used when not expected.
ie if you are not on a call and you are say.. reading thru your emails or typing up a shopping list in the Notes app and you notice the orange light is on, you'd then need to wonder what app is listening in the background.