Well that's one fact that traders would have to live with. So it really just boils down to being selective about which exchange you're going to use. All these exchanges have issues but they of course wouldn't want too many negative ones to smear their reputation. So stick to those that many users are trusting as well and keep a wallet outside exchanges
Ultimately, all crypto exchanges are vulnerable because there are inside jobs and hacks. But if coins get stolen, there is no way back. I don't remember an exchange that got hacked and managed to get all their coins back. In August 2016 over 70M dollar worth of BTC got stolen from Bitfinex, and no one knows for sure what's happened to them since then, apart from the thieves themselves, of course. There's no safety in centralized exchanges. Regulations may help a bit, but crypto will remain crypto and no amount of regulation will prevent future hacks.