it amazes me how retarded they are with basic security shit over there.
especially, given all the money they have behind them now.
No it's not that serious, there was no hack or compromise. Some spammer abused 'Request money' feature of Coinbase with a list he already had from somewhere.
Actually, it is a big deal, because the hack allowed the hacker to place a Name with an email address. It's called user enumeration, and coinbase should have known better. They are absolutely liable, and eventually will be sued over this.