You do realise it's not going to do anything to stop someone recording a conversation without the other person knowing because they CANNOT SEE IT, if I am recording on MY computer and not theirs don't you?
You do realize that there are plenty of scenarios like one spouse installed some kind of secret monitoring software on the other spouse's computer and secretly record their conservations.
https://www.bbc.com/news/technology-50166147
This mic icon protects the other spouse.
Or you downloaded some pirated software which contained spyware (and it turn on the microphone).
People on this thread kept on asking for some simple registry deletion that will turn off the microphone icon. Imagine the spyware delete a few registry items and shuts off the microphone icon when the spyware installs itself onto your computer.
Therefore this mic icon cannot be removed on purpose. I surely hope that Microsoft's security team would not be so stupid that this important security/privacy protection can be defeated by a simple registry deletion.