This is one drawback to using bitcoin, however the pros to using Bitcoin vastly outweigh the cons to using it.
When you deal with an established exchange, the exchange has a good reason to continue to operate honestly because they will generate long-term trading commissions. With a person to person trader on the other hand they can more easily pull off their scam again under a new identity
There is a disincentive to scam, but nothing prevents exchanges from getting hacked.