Because I am against people losing funds, 4100BTC were stolen, that is like a bank heist to me. That means we failed on educating the public and new people that web wallets have so much risk.
I'd never let that much btc get transferred from it in a short period of time without the owners verification (to allow such a large amount of funds to go through it). Then the security measures.. and so on.
How would he have stopped it? They got access to the wallet file copied it and setup their own bitcoind and sent the files, there is no way you can stop that attack. Other than writing your own bitcoind which 90% of the people here can't and probably don't want to do for the fear of breaking it. The moral of the story is don't use web wallets, people are too inexperienced for running that. I have had security training and I went to a top school for CS, I know how to handle these things like the big boys and I have amazing ideas for web wallets, but I will never make that moral decision to put the community at risk.