The behavior of the Debian net-installer is not to install rfkill by default indeed, but is networking soft-killed in Debian by default? Because this is the reason rfkill is needed in the first place.

Read my report carefully, the expected behavior in my report is not to soft-kill (block) networking at all regardless of package rfkill, and to investigate what makes the installer behave this way ONLY WHEN wifi is used during the installation process.

Please do not ruin the bug report, leave it be.