If you try the same thing with say "Time & date prefs", it pauses with an incorrect password for a few seconds, then visually shakes indicating it's a wrong password. With the App Store prefs, it just instantly closes the authentication dialog, even with a blank password.
I don't really understand the logic as to why some panels in preferences have padlocks and others don't... Why does date/time need admin rights whereas Network (delete/add/reconfigure networking), Internet Accounts (delete/add any accounts?), iCloud (do all manner of things), Time Machine (back a machine up elsewhere?) don't require it?
This is also the behaviour of the App Store preferences in version 10.13.1
The global prefs that can be reconfigured by "regular users" (i.e. non-"sharing only" users) are precisely those prefs required to keep the system in a working state if you're physically in possession of it and doing the things that possession of a computer implies. For example, you can move a computer you physically possess to a new location–at which point the same wireless networks won't be available, and maybe you won't be able to get online without a proxy. So, in order to ensure that just going places doesn't necessitate a call to corporate IT, the default† is to let any non-"sharing only" user configure networking.
† "Default" because these prefs can be locked down using a configuration profile (like a windows Group Policy Object) by corporate IT if they need a computer specifically secured against these changes, such as a public-use kiosk.