Hardware wallets are not safe in and of themselves, or because there is an in-built security feature that protects its users, hardware wallets are safe because they store the owners keys offline, and when the keys are offline it is impossible for an attacker to steal it.
With hardware wallets, your private keys will not be exposed to the Internet so that it will keep your coins safely from threats which can steal your coins. With hardware wallets, you can broadcast your transaction, sign it without leaking your private key.
But a hardware wallet isn't just safe on its own, the owner must have great operational security, they must back up the seed phrase generated from the hardware wallet and ensure the physical device is also kept in a safe place and always encrypted with a PIN.
This is about other things like wallet backups which are vital for you when you need to recover your wallets. It belongs to a hardware wallet user and his practice. If a user is careless, does not make wallet backups, and lose his coins because of unable to recover his wallets, it is not responsibility of that hardware wallet producer.
If you build up a good lock but the buyer who buys that lock for his house but leaves the key in front of thief eyes, it is not your responsibility if that house is invaded by a thief.