Huh? Given how most web applications these days are using client-side rendering there's nothing stopping someone from just downloading all of the frontend assets. You can also connect to a server from your desktop application so I don't understand how desktop makes it easier to pirate anything.
Proprietary desktop applications are usually downloaded after a payment, and then the full software is available locally. By hacking the security parts of it one can then have a totally free version and distribute it. That's why it is easier to pirate.
Games and even productivity apps are known to be moving small pieces to their servers so that you cannot run the entire application on your own...
> That's why it is easier to pirate.
There are no technical reasons why a desktop application is inherently easier to pirate. Only implementation details.