Contradictory PATH directions when building on Windows with Visual Studio

I am trying to use git bisect to locate the precise commit that introduced
bug #17299. This bug is present in the official Postgres 14 libpq, but not
in 13. Therefore, I must build libpq from source a bunch of times to find
the offending commit. The documentation says that the official binaries are
built in Visual Studio, so I will use VS myself.

https://www.postgresql.org/docs/14/install-windows-full.html

Early in the documentation, it says: "When building, make sure there are no
tools from MinGW or Cygwin present in your system PATH."

Shortly thereafter, it says: " You will need to add the directory
containing flex.exe and bison.exe to the PATH environment variable in
buildenv.pl unless they are already in PATH. In the case of MinGW, the
directory is the \msys\1.0\bin subdirectory of your MinGW installation
directory."

I find this very confusing. I am not supposed to have any MinGW binaries in
my path while building, then I am required to add MinGW binaries to my path.

I'm guessing that they should indeed be in the PATH and the first
instruction to remove the binaries from the PATH is wrong. Right? Am I
reading this wrong?

I have searched the archives of this list for "Windows path" and found
nothing; please forgive me if I somehow missed a message and this is a
duplicate. Thanks so much.

---
Liam Bowen