What is established practice in " fair dealing" in art that references other work?

There are "samples" used in music, and artists who make use of other people's work. Fair dealing allows commentary and criticism on a work. It is an obtuse argument, that art is a form of commentary or criticism. Is there any established middle ground on that point? My own attempt at an impartial third party view, is that some works comment on society more generally, the work that is referenced is only used as an example that represents a particular time or society.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).