Yes they are hackable. desktop wallets even more so. I am yet to be convinced about the security of hard wallets also, as I know a guy who lost a ton of money during an update of his hard wallet.
You write nonsense. This is not a hacking, phishing, replacement files, which has nothing to do with the code / wallet server (especially if it's offline wallet, which is used by all the appropriate people). And this is completely the fault of the owner of the wallet, nothing more.