If one would have kept IOTA on the exchange, no seeds would have been created and the funds would still sit there.
you prove again that you have no technical knowledge about how cryptos work. Do you really think that exchanges don't generate seeds? Where do you think they store the coins?Perhaps 90% of all wallets used these online seed generators.
There were reportedly 4 million dollars stolen from people who didn't care about the security of their wallet. That's about 0.001% of all wallets
In this case it did not help as the seed, that's how they call their private key, was generated online by malicious sites they promoted in their forum, as their own client did not have the functionality to create such.
The Iota Team warned about online generators. See this post from August 2017 (long before funds got stolen)
"All things considered, seed generators are still not considered safe if they come from a third party source, and not considered best practice. I would caution people against using this tool at this time. (https://forum.iota.org/t/iotaseed-io-now-also-for-generating-paper-wallets/3915)"