Title sounds conspiratorial, but it lines up well with the controversy around TrueCrypt's discontinuation which, I believe, specifically called out BitLocker as an alternative to use in future.
Prevailing theory is they were pressured to put in a backdoor and couldn't disclose it, so they had to make a seemingly ridiculous statement (because who in their right mind would trust bitlocker) to call attention that "something is very wrong"
Alternately, they don't want people to rely on abandonware for security.
Also, despite the conspiracy theories of backdoors I'm not aware of any bitlocker exploits that work on TPM + pin, which is the intended "secure" configuration[1]. All exploits rely on TPM-only (ie. ez-mode), which is basically the security equivalent of running https/ssh without certificates and blindly accepting whatever keys shows up.
[1] https://learn.microsoft.com/en-us/windows/security/operating...
But Windows doesn't need the OS to decrypt a BitLocker volume anyway because the bootloader can do it... otherwise how could a FDE disk ever boot in the first place?
Unless I want to change it... or have multiple OSes/partitions where I need the entire disk encrypted.
Plus if you ever needed to change or reset your password, that complicates the encryption.