this is not true. you can configure bitlocker with or without TPMs.
just google it. also the doc for the powershell command talks about it in the establishing a key protector section
https://docs.microsoft.com/en-us/powershell/module/bitlocker...
I used the `manage-bde` command rather than powershell:
https://docs.microsoft.com/en-us/windows/security/informatio...
The GUI for bitlocker doesn't provide access to all the functionality that manage-bde provides (iirc: if a TPM is present, the passphrase options aren't presented in the GUI. And it used to talk about a "PIN" instead of a passphrase/password, but the "PIN" can (with some gpo tweaking) contain letters/space/punct as well as numbers.