Is this an older model? I could see them turning off or using weak encryption on media if the hardware couldn't keep up with the amount of data they were writing.
I'm in the process of optimizing a bootolader for my various SoC/SBCs and even the cheapest, oldest least powerful SoC from 15 years ago can manage AES-CBC via crypto accelerator at 50 MiB/s. There's no excuse.
As another commenter pointed out, any cheapo ARM core from the last 10 years could do the job Flock needs it to do, as long as it has a (very cheap and common) crypto engine strapped to it.
But, a question for you: even if it was the case that the hardware was the limitation, isn't that also an indictment of Flock? Selling something that cannot exist securely within the bounds of current technology? Or, at a minimum, bad chip selection leading to a compromised design?