So, yes. They never promised it would work on Linux... however, it used to work and they just ♥♥♥♥♥♥♥ borked in on their own.
They could enable Linux users, they chose not to. They could have a seperate non-battleeye mode, they chose not to.

There is no reason, why it shouldn't run on Linux but them just chosing not to allow it. If they are afraid of more cheaters, fine. Why not just making non-battleeye private lobbies a thing?
Win-Win-Win.
But no, you can't have nice things. Welcome to Rockstar Games.

This is the same company that needed more than 2 years to fix a simple issue that made GTA SA not work on Android after an update. A very easy fix was needed. They needed YEARS. While still selling the product.

Is it entirely fair to give a negative review for something they never advertised? Well, it is if they break stuff intentionally.

So, yes. They never promised it would work on Linux... however, it used to work and they just fucking borked in on their own. They could enable Linux users, they chose not to. They could have a seperate non-battleeye mode, they chose not to. There is no reason, why it shouldn't run on Linux but them just chosing not to allow it. If they are afraid of more cheaters, fine. Why not just making non-battleeye private lobbies a thing? Win-Win-Win. But no, you can't have nice things. Welcome to Rockstar Games. This is the same company that needed more than 2 years to fix a simple issue that made GTA SA not work on Android after an update. A very easy fix was needed. They needed YEARS. While still selling the product. Is it entirely fair to give a negative review for something they never advertised? Well, it is if they break stuff intentionally.