Your analogy would make sense if there was a free software replacement for these firmware blobs. Since there isn't, the options are "binary firmware" or "brick". There is no question as to what sort of software to put on these devices, since there is only one option.
If there was a case where you had both non-free firmware and free firmware for the same hardware, and the Linux kernel developers rejected the free firmware on non-technical merits (they will not accept it if it is buggy crap that crashes all the time or introduces a security hole), then you would have a point. I know of no case where that happened.
Not to mention that the whole argument is a bit bizarre. Non-free binary code on flash memory within device = OK; the exact same non-free binary code running on the exact same device but uploaded from the operating system = not OK? Either both are wrong or neither is, since it is the exact same code running in the exact same place doing the exact same things. The only difference being where it is stored while the device is powered off.