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.
Another victim of bitcoin paper wallet dot com: https://www.reddit.com/r/CryptoCurrency/comments/cyd6uj/bitcoinpaperwalletcom_scam_or_not_4_btc_stolen/ .
I use https://www.bitaddress.org for my paper wallets and they also use mouse input for extra entropy, but I see a article posted in 2016 says it is not safe to use it? https://www.newsbtc.com/2016/12/11/bitcoin-users-stop-using-bitaddress-org-look-alternatives/
I have not had one of the 100's of Paper wallets that I created "offline" with this script, being compromised. I used a old second hand computer & printer that were not connected to the internet to create these wallets and then I physically destroyed it.
Anyone else care to explain why https://www.bitaddress.org would not be safe to use?