I'm sorry, but some of these kids have payed hundreds if not thousands of pounds for these items, and if someone logs into your account, and transfers it away, you have lost it and it has cost you in the real world.
It's all well and good saying they could just give it back, but that means when anyone is unhappy with a trade of items that they agreed to, they could say it was stolen, and waste moderator time on non-issues as they determine if it actually was stolen or an agreed trade.
To say it's not theft because, 1, it's virtual and 2 the scammer used phishing techniques is just plain wrong. If someone logged into your online bank account in a similar fashion, you would happily call that theft. Wouldn't you?
Bad analogy. If drugs where licensded and regulated properly, then first off, crack most likely wouldn't exist today, secondaly, if it had been created then we wouldn't have a load of crack dealers in neighboor hoods caushing trouble, getting people hooked etc, just a couple of licensed vendors who would only sell to you if you had the correct license.
If logic, common sense and thought are put into something, the "problems" wouldn't exist to begin with.
So why not work on that, the innovators they are suing are the guys who can do this, spotfiy got it right, by that I mean, managed to not get sued. There are hundreds of other similar services which no longer exist because the music industry just litigated them out of existence.