Anyway, it is not right to store your coins at an exchange. Why you should not do it, I explained above.
While that is true in general, it is not for IOTA as the private key aka seed was compromised in thousands of cases. Perhaps 90% of all wallets used these online seed generators. And there was no protection at all. No authorization, meaning one could not password (or better) protect these private keys.
If one would have kept IOTA on the exchange, no seeds would have been created and the funds would still sit there.