The people that did it.
Certainly, but they had help. Not surprised at this point, but somehow still disappointed to find no mention of "Microsoft", "liability", or even "blame" (beyond the titular question).
If there were liability for the customers' harm, then the makers would design and implement hardware and software with more concern about security and abuse. Not saying Microsoft invented the idea of avoiding responsibility (and actually unable to think of anything that Microsoft actually did invent), but they perfected it. Thereby Microsoft became rich and successful and the model for other companies. Latest reports are pointing the fingers at Chinese manufacturers, but they just sold what the customers wanted, secure in the legal protection of "You can't sue us no matter how much harm our devices cause."
Oh well. Pointless to spend more thought or time on Slashdot these days, especially in speculating on possible improvements. This article will disappear in a few hours, but maybe I missed something "funny"... Okay, found the only post with a funny mod, and it wasn't. Not surprised.