Many of this is actually fearmongering from HWW manufacturers.

I agree a separate device is useful for security, but from there the arguments start to make no sense.

For example, many “attacks” on USB are due to tradeoffs between security and performance (DMA and similar) and devices trusting anything to be what it says like a keyboard.

All the USB stacks on hardware wallets are impossible to attack because they are simple and they don’t allow anyone to just input fake clicks.