How can a motherboard get damaged

If said device malfunctioned - damage to the mobo could result. If the installer in some way damages the interconnects.
-Bruce

The only real way I can see that happening is if the drives physically fall on the motherboard and damage it. I suppose, if you're willing to stretch things a bit, that you could say that using one of those drives to install a BIOS update that goes sideways could damage the board.

The motherboard cannot be damaged by anything connected to the SATA data lines. I suppose that damage could occur in indirect ways mentioned by previous posts, but a faulty CD/DVD hard drive cannot damage the computer.
Why are you asking this question? I have seen computers behave erratically when the DVD drive was connected, but this is due to a faulty power supply.