The definition of "bricked" is not set in stone; a lot of what a normal person would consider "bricked" (doesn't turn on, or turns on to an unresponsive black screen, and no magic sequence of button presses can reset it to working order) could be fixed by a power user with the right equipment, software, and knowledge.
In this case, it requires fairly expensive equipment (another $2.5-10k device), somewhat easy to acquire software, and the appropriate set of instructions, to overwrite the device's broken firmware with a working copy; you don't have to open up the device and plug a JTAG adapter, but using the DFU protocol is very similar to that, since in both cases you're writing directly to the firmware under control of an external device. This is not like "BIOS FlashBack" and similar on non-Apple PCs, in which the device can rewrite its firmware by itself from a common USB stick.
(Also, about data loss: a device with removable storage could get bricked without any data loss, and fixed also without any data loss, simply because the data storage is separated from the firmware and from most of the hardware. It's Apple's insistence on non-removable storage which risks losing data when something else makes the device fail to boot.)
