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.
Well, until you have some evidence that this is happening, you can't condemn the website.
You showed me a link of a newbie that lost hia funds because he didn't take any precaution and didn't follow website recommendations.
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