The original owner
washed his hands of it years ago. He may have sold it to a scammer or he may have broken bad himself. It cannot be trusted.
Did you expect that the former owner of the website do anything different? He said he sold the website and cannot be responsible for it anymore
What did you expect? Like "ok, I sold my website but I can guarantee that the new owner is an honest guy and I am responsible for his actions"
If you sell your site to a scammer then you definitely bear some responsibility. You're setting people up to lose money. The only way to legitimately exit such a business is to sell it to someone you know is honest. Otherwise you don't sell it at all and yes that means you lose out on the gains but it is the right thing to do.
An example of the correct way to do things can be found in the sale of multibit software to keepkey. The multibit developers made sure to sell to a trusted entity in the space. When Keepkey found themselves incapable of maintaining the software they chose to shutdown the project rather than sell it to a malicious entity. They could have sold it and recovered the amount they spent on acquiring multibit but they chose doing the right thing over material gains. All in all no user lost funds and the reputations of all parties involved were maintained.
That's not how things work. And if you properly airgap your computer, the risks of using this website are very low (or non existent)
No, you are mistaken. If the site is malicious it could be programmed to generate private keys known to the site owner. In that case it doesn't need network connectivity to compromise wallets so using it offline doesn't make a damn bit of difference.