I am blaming the developers of exchangers, They have to put more priority on cybersecurity. We know that hackers are using every means and are using different ways to hack. It is like our residence, as arm robbers are using different ways to penetrate people house, people also solidify security of their houses.
You can't blame them at all, there are just people who wants easy money and one of doing this is to hack someones account and steal his/her money and identity. Exchanges also learns from the past and developing the security of their website to a optimum level. We don't know the other vulnerabilities of an exchange just like what happen to etherdelta in which i thought a unhackable exchange but the hackers find a way to penetrate users information by attacking the DNS. I just suggest that these exchanges should update their security and reward those who can see its vulnerabilities.