The theft wasn't due to an issue in the core protocol of Ethereum, it's due to faulty code in a single piece of software (as you can see throughout the rest of the thread).
It's a matter of poor engineering practices, not a flaw in the fundamentals of the protocol.
If an engineer designed a bridge, and it failed due to a flaw in the design -- say the math on a strut's angle was bad and the bridge collapsed causing millions in damages and took a few lives. Do you blame steel, all steel, and everybody who uses steel in construction as foolhardy? Or do you blame the engineer, the safety inspectors, and the company that oversaw the project?