When a person gets code from another source on the internet, they generally know where the code has come from.
What you get paid is to write your own code. When you write your own code, generally you think first and then type. Well, with Copilot you think first and then start typing a few symbols before seeing automatic suggestions. If they are right, you accept changes and if they happen to be similar to any other code out there, you deal with it exactly the same as if you typed those lines yourself.
If you happen to type code that is similar to copyright code, that is generally considered legally OK.
If you copypaste copyrighted code, that is not legally OK.
If you accept that same code from an autocomplete tool, that can easily be seen as equivalent to the latter case rather than the former.