Admittedly, Im not familiar with CAcert, so I dont know how strong proof that is. The link doesnt mean anything to me, perhaps you can elaborate on that? Other than that, there is nothing that proves his ID. Facebook link doesnt even work, and the rest would take a wanna be scammer a few hours tops.
That said, even if we were sure his ID were correct and not stolen, then so what? Its a step up from Pirate perhaps, but when was the last time a bitcoin scammer got convicted in court? Mybitcoin, Bitcoinica, Pirate, .. no one even got in trouble so far.
Maybe he spends some of his own money to pay the interests, after all, for 2.5kBTC that would represent about 300/month, which could be worth a reputation of reliability.
Now think that through.. if he doesnt have a businessmodel that pays for the 100% APR, then why oh why would he pay 300 euro per month just to get a good rep? Thats precisely what a scammer would do, not someone with a genuine profit model.