It's not really advocating for open source games despite evoking Richard Stallman and Free Software.

A lot of people get all up in their feelings when it comes to "private property", like (hypoerbolic) "if they allow redistribution of abandonware, they might take everything" and it's just not justified. It used to be, for example, that copyrights on books weren't automatically granted and they were much shorter terms. You had to apply for copyright renewals. Why? Because of orphaned works and it was viewed that if nobody held an interest that they asserted, it was in the public good to place that in the public domain.

Abandonware follows the same principles. The arguably controversial part is that "abandonware" here includes "forced obsolescence". And I 100% agree that if you, as the publisher, make a game nonfunctional (or even greatly reduced functionality) then people should have the right to make those games work.

The most egregious cases are like Simcity 5, which was made online for literally no reason (other than "because piracy"). They tried to sell online features but that wasn't the reason.

The idea that this kills the entire gaming industry is just slippery slope hyperbola.