I wander where you read it; I am in the dev channel, but I regret to say that what you write is not true. I just had the same message you are referring to.
If you were in the dev channel prior to the 24th June and remained there, you can upgrade to windows 11 even if the device does not meet the currently published specs. Microsoft will monitor the performance on unsupported CPUs but may not fix problems experienced by users of these devices.
To join the Dev channel after 24th June and upgrade to Windows 11, the device must meet the currently published specs.
Windows 11 Specifications - Microsoft
Windows Processor Requirements Windows 11 Supported Intel Processors | Microsoft Docs
Windows Processor Requirements Windows 11 Supported AMD Processors | Microsoft DocsWindows Processor Requirements Windows 11 Supported Qualcomm Processors | Microsoft Docs