This kernel is for people who want to Be Free, rather than to give up freedom in exchange for some short-term apparent comfort. Ideally, this would be everyone, but Stockholm's Syndrome kicks in and the rest is history.
Anyhow, for these people, the blobs are useless, because the very hardware that would require it to function is useless for them, at least until some Free alternative arises.
The FSF, the older sister of FSFLA, maintains a list of hardware (peripherals and complete systems) that are suitable for people like us, who want to live in freedom, or at least in software freedom. http://fsf.org/hardware/
The hardware I use the most is a Lemote Yeeloong notebook.
I don't fully understand your last question, but I'll try to answer what I think you asked. Sorry if I misunderstand, please let me know if you meant to ask something else.
I don't see a significant ethical difference between modifyable software to control a device in semi-permanent memory in the device, or provided by some other software component on a per-session basis.
Both keep the vendor in a position to control and impose its choices on the user and alleged owner of the device.
What makes the latter case worse IMHO is the cost-shifting that the vendor imposes on operating system vendors. The vendor saves the costs of permanent memory, and gets others to replicate and distribute part of the product for them. When the firmware is non-Free, this amounts to enlisting operating system distributors as accomplices in taking freedom away from users.
Distributors don't get any real benefit from that (comparing with vendors shipping the firmware built into the device), they just get their hands dirty. But those who do keep their hands clean and not take part in luring users into the traps may lose if flocks of freedom-unconscious users judge the distributors (or rather the products they distribute) not in terms of polluted their distros are, but rather on how easy and comfortable they make it to use freedom-depriving devices.
In the end, distributors that aim at popularity among the freedom-unconscious face the prisoners' dilemma, enter a race of who adds pollutants faster, and the result is the tragedy of the commons we see now. I addressed this in a bit more detail in the Linux-libre speech at last year's Libre Planet conference. Audio and slides are here: http://groups.fsf.org/wiki/Alexandre_Oliva_%28LP09%29
Now, if the hardware device cannot me modified, period, say because its programming is all rendered in permanent hardware (actual ROM), then freedom #1 can't be exercised anyway, and even freedoms #2 and #3 lose significance (what's the use of improving and distributing something that can't be used without a hardware fab anyway?). The vendor isn't at an advantageous position to tinker with built devices than the customers, so this case is not unethical IMHO.