First Amendment says you cannot ban games for their content; only put prominent warnings/labels about content that is accurate/descriptive within reason. I'd actually advocate for adding in QRcodes to the back that pull up the ESRB entry with more details about the game's content.
When I said 'exclusively benefits the games industry' I meant it benefits the major game publishers/developers as well as the ESA which lobbies heavily to maintain the 'licensed not sold' nomenclature that has become the standard for software both gaming and otherwise.
The ESRB's content ratings aren't the best but neither are any content ratings in any part of the world. They're only a band-aid solution to the absolute glut of trash that floods the games market on a near-daily basis.
Gamers and consumers alike need quality control and curation from multiple sources simultaneously. GoG can't do it alone. We need featured games and recommendations based on our past actually-played-games history. As gamers we should ask ourselves why we spent 500+ hours playing and complaining about terrible games when the good ones sit unwanted, unloved, and unplayed.
I feel the market is slowly starting to shift away from the trash and focusing more on rewarding the treasure. It is very VERY slowly happening but I am starting to finally see this with major AAA companies and their 50% or lower stock prices from their historical peaks. It is a downward spiral that never ends. It just goes on and on my friends...
Community voting & tagging can supplement the self-disclosure provided by (responsible) game developers. While itchio does a decent job of making sure actual literal asset-flips and trash don't get dumped onto this specific market, it is only a matter of time before the itchio staff get overwhelmed and cannot handle things on their own. The community should help with this and be rewarded for doing so. Itch points or whatever for helping to vote/rate/tag stuff accurately and bonus points when other (unique) users are upvoting their tags. We'll ignore downvotes since those are often abused to censor things.
Automation/bribery of any kind results in an automatic permanent blanket ban from the itchio marketplace for that developer and all of their game titles/products. That kind of threat would significantly incentivize game devs to strongly discourage their users from doing anything to set off the botting alarms.
But in hindsight, all of this kinda just seems up in the air and at this rate things may not really make traction on this rating system issue until at least early February 2019.