Honestly, I am figuring Apple blocks the ability to restricts the password app. You can try to use a Software Restriction Policy and block the binary directly with the Jamf Binary, just be very careful when blocking macOS core services as it can have unintended consequences. 

You can use Google Santa, a binary and file access authorization system for macOS.

Have you tried using Restricted Software setting? You may be able to at least force it to close whenever someone tries to open it by checking off the box "Kill process" in Restricted Software.