Only an idiot, or someone who intentionally stuck their head in the sand, couldn't see there was an issue at Gox years before it went belly up. Why people put money there I have no idea. Maybe it wasn't obvious what the problem was (we have more details now) but there was something off and it was only a matter of time. I got the feeling there were a lot of naive younger people who had money/btc there.
It was adviced by plenty of people in the community including Andreas Antonopoulos that people should never put their coins inside anything that isn't their own wallets that the control. People that got scammed by Mt Gox wouldn't listen so it's their fault, they took a risk and they lost, that's how it goes.